Cod liver oil is a concentrated source of vitamins D and A. It also contains certain fatty acids. Vitamin D is synthesised by the body when exposed to sunlight. Since there is plenty of sunlight in India, there is rarely a need for vitamin D supplementation. The normal diet (such as carrots, dark green or yellow vegetables, eggs) contains enough vitamin A. Excessive, regular and/or prolonged intake of vitamin A supplements can lead to toxicity known as hypervitaminosis characterised by fatigue, irritability, loss of appetite, loss of weight, vomiting, low grade fever, loss of hair, dry hair, bleeding lips, anaemia, headache, pains in bones and joints etc.