The *Zhubing Yuanhou Lun* (Treatise on the Pathogenesis and Manifestations of All Diseases) states: In the regions east and south of Sanwu, including various mountainous commanderies and counties, there is a condition known as "water toxicity" found in valleys and stream sources. It frequently occurs in autumn. This disease is also known as Zhongshui (Water Poisoning), Xizhong (Stream Middle), Zhongsan (Stream Splash), Shuizhongbing (Water Disease), or Xiwen (Stream Warmth). Nowadays, when people enter streams and fall ill, because its symptoms resemble those caused by the bite of the Shegong (a toxic aquatic insect), it is commonly referred to as Xibing (Stream Disease). However, there are differences: cases with sores are caused by the Shegong, while those without sores are Xibing.

The *Ge Shi Fang* (Prescriptions by Master Ge) states: At the onset of water toxicity, patients experience aversion to cold, slight headache, pain in the eye sockets, mental restlessness and vexation, trembling of the four limbs, lower back pain, stiffness of bones and joints, pain in both knees, or a slight fever. They desire sleep; they are clear-headed in the morning but worsen in the evening. The fingertips of hands and feet become cold up to the elbows and knees. After two or three days, worms may develop in the abdomen, eating away at the lower organs. There will be sores in the anus that do not itch or hurt, making them imperceptible until visually inspected. If not treated immediately, after six or seven days, the lower region will suppurate and ulcerate. The worms will ascend to devour the five zang organs. With intense heat, severe vexation and toxicity, and uncontrollable diarrhea, death will occur within eight or nine days, beyond the capacity even of skilled physicians. Upon feeling unwell, one should immediately inspect the lower region. If there is a sore bright red like cut meat, the toxicity is most acute; if the sore resembles the teeth of a conch fish, it is Yin Toxicity, which is slightly less urgent, yet still fatal within twenty days. To determine if it is Zhongshui, do not boil several dou of water. Instead, take five sheng of small garlic, chop it, and add it to the bathwater. Do not let the water be too hot, as excessive heat diminishes the potency. Strain the dregs, adjust the temperature to suit, and bathe the whole body. If red spots or patterns appear on the body, it confirms water poisoning. If there are no such signs, treat according to other diseases. The treatment prescriptions are as follows:

Take plums or peach/jujube fruits, crush and squeeze to obtain approximately three sheng of juice. If the juice yield is low, add water and squeeze again.

Another prescription: Take Changsi Cao (Houttuynia cordata), crush and squeeze to obtain one or two sheng of juice. Use cotton soaked in the juice to apply to the lower region, three times daily.

Another prescription: Crush Lanqing (Isatis leaf/Indigo naturalis), mix with a small amount of water, and apply to the head, face, and body evenly. (This matches the *Qianjin Fang*).

Another prescription: Take a handful of Liao (Polygonum hydropiper), crush thoroughly, mix with one cup of wine, squeeze, and drink the juice.

For cases where sores have already formed and ulcerated in the lower region:

Take peach bark and leaves, crush thoroughly, soak in water until thick, strain, pour into a basin, and sit in it for soaking to expel the worms.

The *Qianjin Fang* (Essential Prescriptions Worth a Thousand Gold) provides a prescription for water toxicity:

Crush Xiancao (Xanthium fruit) to extract juice, take one sheng orally. Soak cotton in the juice and apply to the lower region, three times daily.

The *Jiyan Fang* (Collected Proven Prescriptions) offers a secret prescription for Zhongshui:

Dry Shuiping (Lemna minor) in the sun, and administer one cunbi (square-inch measure) with wine.

Another prescription: Crush Meiye (Plum leaf) to extract juice, take half a cup. For children who cannot drink it, apply it to the nipple for them to suck.

The *Fan Wang Fang* (Prescriptions of Fan Wang) states: Qinglong Tang (Green Dragon Decoction) treats Zhongshui with alternating chills and fever:

Shengma (Cimicifugae Rhizoma) (2 liang), Longdan (Gentianae Radix) (1 liang), Weirui (Anemarrhenae Rhizoma) (1 liang), Daqing (Indici Folium) (1 liang).

These four ingredients are chopped, boiled in four sheng of water to reduce to two sheng, and divided into two doses. If mental agitation recurs, add one Xiao Fuzi (Aconiti Lateralis Radix Praeparata), broken into four pieces, and divide into three doses for good effect.

It also states: For treating ulcerated sores in the lower region caused by water exposure, which physicians cannot cure: Moxibustion on Qionggu (Sacrococcygeal joint) for fifty moxa cones is effective.