Taking large doses of vitamin B every day wards off mosquitos.
Vitamin B supplements are often recommended in the popular media as a systemic repellent against mosquitoes. The theory is that mosquitos don't like the smell of people who take vitamin B.
But research shows that vitamin B is NOT effective. Other home remedies such as brewer's yeast, garlic, bananas, onion, etc aren't proven to repel mosquitos either, although some people swear by them.
Tell people it's best to stick with products that contain DEET (OFF!, Repel, etc). Products with higher concentrations don't work better...they just last longer. For adults, suggest 10% to 50% DEET...these last 2 to 6 hours. Suggest up to 30% DEET for children over 2 mo old. People used to worry that DEET was toxic. Reassure patients that it's safe when used as directed.