How did the early colonists deal with illness?

As to be expected, medical knowledge during the colonial days was lacking for the most part. Illnesses such as smallpox, malaria, and dysentery ravaged entire settlements in some cases. To deal with these illnesses, a lot of measures were taken; some were valid and others were not.
Smallpox was by and large one of the worst illnesses for the early colonists. However, a portion of the population had built up immunities from the old world outbreaks. To combat smallpox, many were inoculated with the live virus. This worked for some but proved disastrous for others, primarily those with poor diets. Another measure was total isolation. In fact, many colonies passed quarantine acts, such as Massachusetts in 1731.
These were two examples of valid measures against illnesses. Other ways the colonists dealt with illnesses were not necessarily valid but did have some truth to them. For instance, many believed malaria came from breathing in air around stagnant water. Although the air did not cause the malaria, the mosquitos around the stagnant water did. These are just two of the many illnesses experienced by the colonists and the ways that they dealt with them.
https://tullyhistoricalsociety.org/tahs/medical.php