Female mosquitos search for a host search using a combination of different stimuli, including chemosensory, thermal or visual impulses. It is smell (chemosensory) that is the critical signal that identifies the presence of the host to mosquitoes. The host odour is a complex mixture of chemicals and volatile compounds produced by skin microflora that induce electrophysiological and behavioural responses in mosquitoes. These compounds include, for example, lactic acid, ammonia, various ketones, sulphides, or carboxylic acids. The female mosquito perceives the odours of the host through olfactory receptors that can be found on the antennae or in the area of their mouthparts. A preference for human hosts, which we refer to as anthropophily, was developed by some mosquito species only later in evolution. This was made possible by changes in their genetic information, precisely at the level of olfactory receptors - anthropophilic mosquitoes are characterized by an increased expression of genes encoding these receptors. The identification and further study of specific genes responsible for the expression of olfactory receptors could in the future lead to the invention of such protective means that would once again change the preference of mosquitoes to other hosts and thus limit the spread of various infectious diseases, which mosquitoes are the carriers of.