It is believed that mixing honey in a hot drink makes the beverage toxic. However, this statement is not entirely correct. The problem is with heating the honey. It is a common notion that heating anything with sugar can release a chemical called 5-hydroxymethylfurfual or HMF, which is carcinogenic in nature.
As per a study carried out by the National Center for Biotechnology Information, honey, when heated (>140°C) and mixed with ghee produces HMF which may act as poison in due course. When we put it in milk, the optimal temperature of the beverage is much less than 140 degrees. So it’s better not to heat honey. Boil the milk and let it cool down for 10 minutes before adding honey in it.