 Chopra then returned to Canada where he worked with Health Canada, first as a senior scientific advisor in the Bureau of Drugs until 1987, and then in the Bureau of Veterinary Drugs until 2004.In 1998 he became a member of the rBST gaps analysis team at Health Canada, investigating effects of bovine growth hormone in milk and human vulnerability to this molecule produced by genetic engineering.His opinion was that approval of this dairy enhancement was not warranted.