# Laser Therapy Side Effects in Dogs: What to Know Most dogs handle therapeutic laser treatment well, and serious dog laser therapy side effects are uncommon when the equipment and settings are right. The realistic risks are skin burns, eye injury from stray light, and a small chance of temporary soreness or restlessness after a session. The biggest danger is treatment given to a dog who should not receive it at all. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - The most common problems are mild and short lived: warmth at the treatment site, slight redness, or a dog who seems a bit tired or a bit wired for a few hours. - Burns are possible when the laser is set too high, held too long in one spot, or used on dark or thin skin without adjusting the dose. - Eye damage is a real risk. Everyone in the room, including you and your dog, should wear the protective goggles the clinic provides. - Laser therapy should be skipped or delayed over tumors, over the eyes, over a pregnant belly, and on dogs with certain bleeding or clotting problems. Your veterinarian decides this case by case. - Ask about the device, the wavelength, the dose, and who is operating it before you agree to the first session. ## What Dog Laser Therapy Is and Why It Is Used Therapeutic laser, also called photobiomodulation or low level laser therapy, uses specific wavelengths of light to interact with tissue. The light does not cut or burn when it is used correctly. It is applied through a handpiece that the operator moves over the skin in a pattern. Veterinarians use it for many conditions. Common reasons include arthritis and joint pain, soft tissue injuries, surgical incisions, wounds, and chronic skin problems. It is often one part of a larger plan that includes medication, weight control, and activity changes. Research in dogs is still growing. One study looked at laser applied to the heads of working dogs and found that behavior measures changed in some groups, with improvements mainly in the group treated with a 1064 nm wavelength [1]. That does not mean laser treats behavior problems in every dog. It means the effects of light on tissue are being studied, and different wavelengths can act differently [1]. Laser is also used for specific skin and inflammatory conditions. A case series described three dogs with calcinosis cutis, a hard skin condition linked to hyperadrenocorticism, who received a dual wavelength near infrared laser as an add on treatment [2]. The protocol used 3 sessions in week 1, then every 72 hours in week 2, then weekly, with 4 J/cm2 at the first session and 2.03 J/cm2 after that [2]. Those numbers come from that specific protocol and are not a general recipe for your dog. Laser has also been used alongside medication for a dog with chemotherapy induced phlebitis, a painful vein inflammation after an IV drug [3]. In that case, low level laser therapy was part of a combined plan that also included corticosteroids and oral medications, and the dog improved [3]. One more point that matters for safety: laser is not the same as every light based treatment. Fluorescence photobiomodulation is a different approach studied in lab grown canine skin cells, and that research looked at cell viability and bacteria, not at side effects in living dogs [4]. If your clinic offers a light based service, ask exactly what it is. ## How to Prepare for Your Dog's Laser Session Preparation is simple, but a few steps make the visit safer and smoother. First, tell your veterinarian about every medication and supplement your dog takes. Some drugs affect bleeding, skin sensitivity, or how the body handles heat. This matters if your dog takes anything for anxiety, infections, thyroid disease, heart disease, or seizures. If you want background on how those drugs can cause their own side effects, these guides may help: [Dog Anxiety Medication Side Effects: What to Watch For](/knowledge/veterinary-medicine/anxiety-and-behavior-support/dog-anxiety-medication-side-effects), [What Are the Side Effects of Antibiotics in Dogs?](/knowledge/veterinary-medicine/pet-medication-guide/dog-antibiotics-side-effects), and [What Are the Side Effects of Seizure Medication in Dogs?](/knowledge/veterinary-medicine/pet-medication-guide/seizure-medication-side-effects-dogs). Second, be honest about your dog's temperament. Some dogs lie still for laser. Others need a helper, a muzzle, or a mild sedative. A moving dog is a dog who can be treated in the wrong spot or for the wrong amount of time. Third, ask who will run the machine. In many clinics a trained technician handles the handpiece under veterinary direction. Ask how that person was trained and how often they do this. Fourth, ask about eye protection. The clinic should provide goggles for the operator, for anyone else in the room, and for your dog when the treatment area is near the head. Fifth, ask what the plan is. How many sessions, how far apart, and how you will judge whether it is working. Pain scores, lameness checks, and photos of wounds or skin are reasonable ways to track progress. Finally, ask what it costs per session and whether packages are offered. Prices vary by clinic and region, so there is no single number to expect. ## What Happens During a Laser Session Most sessions are short. A small area might take a few minutes. A large area or a full body protocol can take longer. Your dog usually lies on a table or on the floor. The operator may clip hair away from the treatment area because hair blocks light. The handpiece is pressed lightly against the skin or held just above it, depending on the device and the protocol. You may hear the machine hum. You may feel mild warmth if you touch near the treated area. Your dog may relax, and some dogs fall asleep. The operator moves the handpiece in a set pattern so no single spot gets too much light. This movement is one of the main safety features. A stationary handpiece held too long in one place is how burns happen. Eye protection stays on for the whole session. Do not lift your goggles to look at the beam, even briefly. Do not let children in the room unless the clinic approves it and provides eye protection for them too. If your dog shows pain, tries to bite, or cannot settle, the session should stop or be rescheduled with better handling or sedation. That is a normal part of safe practice. ## Recovery Timeline and Home Care Most dogs go home the same day with no special care. The table below shows what is typical. Your veterinarian's instructions come first. | Time after session | What you may see | What to do | |---|---|---| | First few hours | Mild warmth or pinkness at the treated area, drowsiness, or restlessness | Let your dog rest. Offer water. Skip rough play for the day. | | 24 hours | Redness and warmth should be fading. Behavior should be back to normal. | Check the skin once. Call the clinic if redness is spreading or your dog seems painful. | | 2 to 3 days | Some dogs seem more comfortable. Others show no change yet. | Keep a simple log of stiffness, limping, appetite, and mood. | | 1 to 2 weeks | With repeated sessions, many owners notice easier movement or less licking at a wound. | Bring your log to the next visit so the plan can be adjusted. | | Between sessions | Skin should look normal. | Do not apply heat, ice, or creams to the treated area unless your veterinarian says to. | Home care is mostly about observation. Keep the treated area clean and dry. Do not rub or massage it hard right after a session. If your dog has a wound or incision, follow the wound care instructions you were already given. If your dog takes other medications, keep giving them on schedule. Laser is an add on treatment, not a replacement for pain medication, antibiotics, or other prescribed drugs. ## Possible Complications and Warning Signs ### Burns and Skin Injury Burns are the most direct risk. They happen when the dose is too high, the handpiece stays in one spot, or the settings are not adjusted for the dog's coat and skin. Dark coats, thin skin, and bony areas absorb and hold heat differently than thick furred areas. Signs of a burn include redness that gets worse instead of better, swelling, blistering, darkening of the skin, or an open sore. A burn can show up hours after the session. If you see any of these, call your veterinarian the same day. ### Eye Damage Laser light can injure the retina and other parts of the eye. This is why goggles are required for everyone in the room. Damage can happen fast and may not be obvious right away. Signs to watch for include squinting, pawing at the eye, redness, cloudiness, or a dog who seems to be seeing poorly. Eye problems after laser exposure are an emergency. Go to a veterinarian right away. ### Pain or Restlessness After Treatment Some dogs seem sore or agitated for a few hours after a session. This is usually mild and passes. If your dog is crying, pacing, panting, or refusing to be touched at the treated area, that is not normal. Call the clinic. ### When Laser Should Be Avoided Laser is not right for every dog. It should be skipped or delayed in several situations. - Over or near the eyes, because of the risk of eye damage. - Directly over known or suspected tumors, because light can affect cell activity and the effect on cancer tissue is not well established in veterinary research. - Over a pregnant belly, because the effects on a developing puppy are not well established. - On dogs with certain bleeding or clotting disorders, or on dogs taking drugs that affect clotting, because light can change blood flow in tissue. - Over areas with active infection, open burns, or unexplained skin lesions until a veterinarian has looked at them. - On dogs who cannot stay still and cannot be safely handled, unless the plan includes sedation. Your veterinarian makes the final call for your dog. If you have doubts, ask why laser is being recommended and what the alternatives are. ## Questions to Ask Your Veterinarian Before Treatment Bring this list to your first visit. The answers tell you a lot about how carefully the clinic runs its laser program. - What condition are we treating, and what result do you expect? - Which device and wavelength will you use, and what dose? (Dose is set by your veterinarian based on your dog's weight, coat, skin, and condition.) - Who will operate the laser, and what training do they have? - How do you protect my dog's eyes and mine? - How many sessions, how often, and how will we measure progress? - What side effects have you seen in your practice, and what should I watch for at home? - What are the alternatives if laser does not help? - What is the cost per session, and are there packages? If a clinic cannot answer these clearly, consider a second opinion before starting. ## Limitations and When to Contact a Veterinarian No treatment is risk free, and laser is no exception. The research on laser in dogs is still developing, and much of what is known comes from specific conditions and specific protocols [1][2][3]. Your dog's situation is individual, so a veterinarian who examines your dog needs to guide the plan. Call your veterinarian the same day if you notice: - Redness, swelling, blistering, or darkening of the skin at the treated area. - A sore that was not there before the session. - Your dog crying, pacing, or refusing to be touched at the treated area. - Vomiting, diarrhea, or a sudden change in appetite after a session. - Any new limping or stiffness that is worse than before treatment. Go to an emergency clinic right away if you notice: - Squinting, pawing at an eye, redness in the eye, cloudiness, or sudden vision problems. - A burn that is open, weeping, or looks deep. - Trouble breathing, collapse, or severe pain. - A seizure or a sudden change in awareness. Schedule a routine visit if progress stalls. If three or four sessions have passed and you see no change in pain, movement, or the skin problem, ask whether the plan should change. Sometimes the answer is a different dose, a different wavelength, or a different treatment entirely. ## Frequently Asked Questions ### Is laser therapy painful for dogs? Most dogs tolerate it well and many relax during sessions. The handpiece usually feels like mild warmth. If your dog flinches, pulls away, or tries to bite, the session should stop and the plan should be adjusted. ### Can laser therapy cause cancer or make a tumor worse? This is not well established in veterinary research. Because light can affect cell activity, most veterinarians avoid treating directly over known or suspected tumors. Tell your veterinarian about any lump or bump before treatment starts. ### How soon would side effects show up? Skin changes usually appear within a few hours to a day. Eye problems can show up quickly after exposure. If you see squinting or pawing at an eye, treat it as an emergency and go in right away. ### Can my dog have laser therapy if she is on other medications? Often yes, but it depends on the drug. Medications that affect bleeding or clotting deserve extra caution. Give your veterinarian a full list of everything your dog takes, including supplements, before the first session. ### Do I need to stay in the room during treatment? Many clinics invite owners to stay, and some prefer it so the dog stays calm. If you stay, you must wear the eye protection the clinic provides and keep it on for the entire session. If you cannot keep goggles on, wait in the lobby instead. ## Related Articles - [Dog Anxiety Medication Side Effects: What to Watch For](/knowledge/veterinary-medicine/anxiety-and-behavior-support/dog-anxiety-medication-side-effects) - [What Are the Side Effects of Antibiotics in Dogs?](/knowledge/veterinary-medicine/pet-medication-guide/dog-antibiotics-side-effects) - [What Are the Side Effects of Thyroid Medication for Dogs?](/knowledge/veterinary-medicine/pet-medication-guide/dog-thyroid-medication-side-effects) - [What Are the Side Effects of Vetmedin for Dogs?](/knowledge/veterinary-medicine/pet-medication-guide/vetmedin-side-effects-dogs) - [What Are the Side Effects of Seizure Medication in Dogs?](/knowledge/veterinary-medicine/pet-medication-guide/seizure-medication-side-effects-dogs) - [Dog Ear Infection Treatment Side Effects](/knowledge/veterinary-medicine/clinical-methods/dog-ear-infection-treatment-side-effects) - [Laser Therapy for Dogs: Arthritis and Surgery Recovery](/knowledge/veterinary-medicine/senior-and-chronic-care/dog-laser-therapy-arthritis-surgery) ## References 1. [Transcranial photobiomodulation therapy with 808 nm and 1064 nm can affect different behavior parameters in dogs](https://pubmed.ncbi.nlm.nih.gov/42315691/). Lasers in medical science, 2026. 2. [Effectiveness of Multiwavelength Locked System laser therapy for calcinosis cutis in 3 dogs: a case series](https://pubmed.ncbi.nlm.nih.gov/41265032/). American journal of veterinary research, 2026. 3. [Case Report: Chemotherapy-induced phlebitis in a dog: diagnostic approach and management strategies](https://pubmed.ncbi.nlm.nih.gov/41122705/). Frontiers in veterinary science, 2025. 4. [Effect of Fluorescence Photobiomodulation on Canine Progenitor Epidermal Keratinocytes With and Without Staphylococcus pseudintermedius Colonisation](https://pubmed.ncbi.nlm.nih.gov/42082164/). Veterinary dermatology, 2026. ## Further Reading - [American Veterinary Medical Association: First Aid Tips for Pet Owners](https://www.avma.org/resources-tools/pet-owners/emergencycare/first-aid-tips-pet-owners) - [Merck Veterinary Manual: Dog Owners](https://www.merckvetmanual.com/dog-owners) - [Cornell Richard P. Riney Canine Health Center: Canine Health Information](https://www.vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-information)