marmite is believed to be useful as a mosquito repellant..
From wikipedia:
Marmite and mosquitoes
Some suggest that the consumption of Marmite can ward off mosquitoes, the reasoning being that the skin gives off a scent, unnoticeable to humans, but which mosquitoes find unappealing, or that the vitamin B content wards off the flying pests. British travellers to tropical locations sometimes take Marmite with them to eat during the trip, although it has been shown that the B vitamin complex does not repel mosquitoes. The root of this belief might have been its use during the 1934–5 Malaria Epidemic in Sri Lanka:
“ The two things given to each patient were a bottle of the standard quinine mixture and Marmite rolled into the form of vederala's pills. The latter was said to have been the idea of the late Dr. Mary Ratnam and to have been more effective than the quinine itself, such was the degree of starvation among the peasantry. The Suriya Mal workers were amazed to see how this little Marmite revived them and put some life back into them. ”
—George Jan Lerski
