A common oral dose is 1 mg per lb (2 mg/kg) every 8–12 hours, after your vet says it’s appropriate.

A 60-lb dog commonly falls in the 55–110 mg diphenhydramine range per dose, with timing set by a veterinarian and the product label.

A 70-pound dog often lands near 60–130 mg of diphenhydramine per dose, but your veterinarian should confirm the right amount.

A common starting dose is 25 mg of plain diphenhydramine per dose for a 25-lb dog, given every 8–12 hours only if your veterinarian says it fits your dog.

A common diphenhydramine dose is 1 mg per pound every 8–12 hours, so a 40-lb dog is 40 mg per dose when approved.

A common diphenhydramine range is 1 mg per pound, so a 5-lb dog is around 5 mg per dose with vet approval.

A common diphenhydramine dose for a 30-pound dog is 30 mg per dose, given every 8–12 hours, using a plain product with diphenhydramine only.

For a 3-year-old, diphenhydramine is usually avoided unless a doctor says to, and the dose is chosen by weight from the label.

A 20-lb dog often gets 20 mg diphenhydramine per dose, given every 8–12 hours when a vet says it fits.

Many vets use diphenhydramine 2–4 mg/kg; a 15-lb dog is 14–27 mg per dose, only with a vet’s OK.