Beri-beri, also known as vitamin B1 deficiency disease. Vitamin B1 is an essential nutrient required by the human body, involved in several important biochemical reactions and crucial for energy metabolism within the body. Deficiency in vitamin B1 can lead to a range of abnormal symptoms in the nervous system and muscles. In adults, early symptoms of vitamin B1 deficiency include weakness and a heavy feeling in the lower limbs, muscle soreness, particularly noticeable in the calf muscles. These are also important early signs for the detection of beri-beri, which are typical manifestations. Additionally, beri-beri may also present with loss of appetite, weight loss, digestive disorders, and constipation. There are generally two types of beri-beri: dry beri-beri and wet beri-beri. Dry beri-beri primarily involves neurological symptoms, chiefly abnormal sensations, numbness, and a burning pain in the hands and feet. Wet beri-beri, on the other hand, is mainly characterized by edema and cardiac symptoms.