This photoacoustic imaging (PAI) in medicine paper started with an introduction to PAI and the famous photoacoustic techniques including photoacoustic tomography (PAT), multispectral optoacoustic tomography (MSOT), photoacoustic microscopy (PAM), raster-scan optoacoustic mesoscopy (RSOM), and photoacoustic elastography (PAE). A modest review about noncontact laser ultrasound (LUS), having the advantage of operator-independent image quality, has been also demonstrated. A concise review of most of PAI's medical applications is demonstrated including cancer screening (for breast, thyroid, ovarian, prostate, lung, and skin), tissue oxygenation measurements, brain imaging, imaging-guided surgery (IGS), and the guidance of high intensity focused ultrasound (HIFU). Some safety considerations contributed with medical ultrasound and lasers have been then presented. In conclusion, more scientific and clinical development in the field of PAI is expected, and an increase in approved devices that utilize PAI's techniques in medical applications is also expected to serve wide sectors of medicine, whether diagnostic or therapeutic.