Eccrine sweat is a water-like fluid secreted by eccrine sweat glands that comprises various kinds of biochemical components such as electrolytes, metabolites, organic molecules, and drugs. The quantitative measurement of these constituents via wearable microfluidic sensors facilitates the noninvasive and real-time monitoring of daily health status as well as disease progression. This next-generation sensor technology has already found use in fields including sports, worker safety, environmental exposures, and medical care.