患 medical patient

This is basically the loyalty kanji (忠)TWICE - one on top of the other.So you could say,
Genghis KHAN was admitted as a patient to the hospital. Since he depended for his life on the doctor, he was DOUBLE LOYAL to the doctor.

a patient ★★☆☆☆
患 (medical patient) + 者 (professional) = 患者 (a patient)

a patient. Easy to remember because in California the かんじゃ can legally get ガンジャ.