Safety Information

• Comfortis starts killing fleas within 30 minutes and provides a full month of protection.
• It is approved for dogs 14 weeks and older and cats 14 weeks and older, weighing the appropriate minimum pounds for their formulation.
• Most side effects are mild but can include vomiting, diarrhea, lethargy, and loss of appetite.
• If vomiting occurs within an hour of dosing, consult your vet; another full dose may be needed.
• Comfortis should not be used in pets with a known allergy to spinosad.

Warnings 

• Not for use in puppies or kittens younger than 14 weeks.
• Use caution in pets with pre-existing seizure disorders, as rare neurologic effects have been reported.
• Avoid accidental ingestion by humans—keep out of reach of children and other animals.
• Contact a veterinarian immediately if you suspect an overdose or adverse reaction.

Human Warnings

• For animal use only.
• Wash hands after handling tablets.
• In case of accidental ingestion, seek medical help immediately.
• Do not handle the product if you are allergic to its active ingredient, spinosad.

References

1. Elanco. Comfortis® (Spinosad) for Dogs and Cats. Elanco, 2025, https://my.elanco.com/us/comfortis.