Yes, Lady-of-the-night is toxic to dogs!
Dogs accidentally consuming the Lady-of-the-night plants can show the following clinical symptoms: Vomiting, Prolonged Depression, Incoordination, Hypersalivaton, Sleepiness Or Excitation, Dilated Pupils, Low Body Temperature, Low Blood Pressure, Coma, Seizure And Death (In Rare Cases).
Lady-of-the-night consumption is also toxic to Cats and Horses.
Toxic Principles Of Lady-of-the-night: Brunfelsamidine.
More Info About The Lady-of-the-night Plant
Scientific Name: Brunfelsia species
Family: Solanaceae.
Also known as: Yesterday, Today, Tomorrow, Kiss-Me-Quick, Morning-Noon-and-Night, Fransiscan Rain Tree.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.
