Is it permitted to enter a study where there is a significant chance you will be given malaria and cured soon thereafter for a few thousand dollars recompense?
Rav Shlomo Zalman Aurbach ztz"l summarized the rules of a healthy person participating in a medical experiment like this: A healthy person may participate in a medical experiment only if there is no danger or suffering involved other than minor discomfort such as drawing blood. If a dangerously ill patient is in need of a life saving treatment, a healthy person is allowed to expose himself to some danger or suffering to save the patient’s life, e.g. to donate a kidney. A non-seriously ill patient without pain or suffering should not participate in potentially dangerous experiments. The payment is not a factor in this rule.