Verdict: No, dangerous
Lemons are dangerous for dogs due to compounds found in the fruit, peel, and seeds. Ingestion can lead to gastrointestinal upset, photosensitivity, and neurological issues. Seek veterinary attention if your dog consumes lemons and shows severe symptoms.
Psoralens are phototoxic compounds that can cause dermatitis and photosensitivity. Essential oils can irritate the gastrointestinal tract and, in large quantities, may cause central nervous system depression.
Psoralens (furocoumarins), essential oils (limonene, linalool)