Background Pears have been world-widely used as a sweet and nutritious food and a folk medicine for more than two millennia. Methods We conducted a review from ancient literatures to current reports to extract evidence-based functions of pears. Results We found that pears have many active compounds, e.g., flavonoids, triterpenoids, and phenolic acids including arbutin, chlorogenic acid, malaxinic acid, etc. Most of researchers agree that the beneficial compounds are concentrated in the peels. From various in vitro, in vivo, and human studies, the medicinal functions of pears can be summarized as anti-diabetic,-obese, −hyperlipidemic, −inflammatory, −mutagenic, and -carcinogenic effects, detoxification of xenobiotics, respiratory and cardio-protective effects, and skin whitening effects. Therefore, pears seem to be even effective for prevention from Covid-19 or PM2.5 among high susceptible people with multiple underlying diseases. Conclusion For the current or post Covid-19 era, pears have potential for functional food or medicine for both of communicable and non-communicable disease.