Mushrooms have oxalic acid. Pleurotus ostreatus is a natural vegetable and can also be planted artificially. Traditional Chinese medicine believes that arrowhead is sweet, produces fluid and moistens the lungs, tonifies the middle energizer and benefits qi, and has a unique curative effect on diseases such as strain, cough and asthma. Wash the skin and attachments of arrowhead. Because it contains oxalic acid, it needs to be boiled in water for 4 minutes and then washed. The scientific name is Sagittarius, a perennial herb of Alismataceae, born in paddy fields, with arrow-like leaves and white flowers. There are bulbs in the ground, yellow or bluish white, which are eaten as vegetables. You can eat. Also known as Ji. This variety is different from the original variety, the plant is tall and stout, the leaves are wide and thick, the top lobes are obtuse to wide oval, and the end of stolon expands into bulbs, which are oval or spherical, reaching 5-8×4-6 cm. Panicles are tall, 20-60 cm long, sometimes reaching more than 80 cm. Insert it in the lower part with 1-2. Fruit receptacle oblate, 4-5 mm in diameter and about 3 mm in height. The seeds are brown and have small protrusions.