Lack of Vitamin-B₁, causes the disease _______.

Deficiency disease:

1. A lack of key dietary nutrients, particularly a vitamin or mineral, causes deficiency illness.
2. Beriberi, commonly known as thiamine deficiency, is an illness caused by a vitamin B₁ deficit.
3. It is more common in underdeveloped countries among persons who eat a diet high in white rice or starchy foods.

Final answer:

Lack of Vitamin-B₁ causes the disease Beriberi.