The role and contraindications of vitamin A include: 1. Role: Patients see in the dark, adapt to a longer period of time, or completely invisible in dark places, clinically vitamin A is mainly used for the treatment of night blindness. It can also brighten the eyes, relieve vision loss, as well as promote the growth of skin tissue cells and moisturize the skin; 2. Contraindications: Patients with arteriosclerosis are prohibited from taking vitamin A because it can aggravate arteriosclerosis, and they need to consult a doctor when using vitamin A.