No, cats cannot eat lemon due to harmful oils and compounds found in the fruit.
Lemon is a citrus fruit that belongs to the flowering plant family, Rutaceae. It contains vitamins C and B—most notably thiamin, riboflavin, and niacin. The juice of the fruit is commonly used to enhance the flavour of many dishes, pastries, and desserts.
Similar to dogs, cats cannot consume lemons because the essential oils and compounds found on its peel, seeds, and leaves are very harmful to them. These toxic compounds include psoralens, linalool, and limonene. Psoralens can make your cat’s skin burn when exposed to sunlight. Linalool, on the other hand, can cause gastrointestinal upset.
What to do if your cat accidentally eats lemon: A small lick of lemon won’t harm your cat. However, ingesting the lemon peel, drinking lemon juice, or inhaling lemon essential oil may lead to health complications. Try to find out how much lemon your cat ate and inform your veterinarian of your findings.
More importantly, watch your cat for any of these symptoms in the coming days: vomiting, diarrhea, depression, excessive drooling, photosensitivity, lethargy, skin irritation or rash, weakness, cold limbs, liver failure, tremors, collapse, and low blood pressure.
In summary: Lemon is not only an ingredient used for eating, but it is also used for cleaning purposes. As such, be careful where you keep your lemon fruits and lemon-scented sprays are stored. Place them in areas where your cat won’t be able to reach them. If you own a lemon plant, make sure your cat does not have access to it.