Lychee contains vitamins C and B6, niacin, riboflavin, folate, copper, potassium, phosphorus, magnesium, and manganese.
Risks
Lychee is high in sugar, which can lead to obesity and other health issues in cats if consumed in large amounts.
The seeds and skin of lychee are not safe for cats and can be toxic.
Suggestions
If you choose to give your cat lychee, only offer the flesh in very small amounts and ensure all seeds and skin are completely removed.
Note: even if labeled as safe, any food can potentially cause allergies. When introducing a new food, please feed a small amount and observe your cat for any allergic reactions.