root of all illness; source of all diseases
Proverbial expression often used in health advice to say that something (e.g., stress, poor diet) is the underlying cause of many illnesses.
Stress is said to be the root of all illness.
Lack of sleep is the source of all kinds of diseases.
Standard kanji spelling for this set phrase.
Common variant with もと written in kana.
A set phrase combining 万病 (all kinds of diseases) and 元 (source, origin). The exact origin is uncertain, but it reflects a traditional belief that many illnesses share a common root cause.