They died of severe cold, according to Dolpa district's Chief District Officer Krishna Prasad Khanal.
All the three were rushed to a nearby hospital in the neighbouring Surkhet district for treatment but died.
Meanwhile, many people who reached the highland meadows to pick the Yarsagumba herb, the valuable caterpillar fungus, began to return after suffering from cold related diseases.
Around 47,000 people have registered their names with the police for picking up Yarsagumba. Many others are said to have reached the highlands illegally.