Symptoms include:

- Dizziness

- Backache

- Tiredness

- Weakness

- Insomnia

- Frequent dreams

- Sexual dysfunctions; premature ejaculation or impotence.

Shenkui is a culture bound syndrome native to China in which the individual suffers somatic symptoms with anxiety, believed to be caused by a loss of semen. And in Traditional Chinese Medicine, shen (kidney) is the reservoir of vital essence in semen (ching) and k’uei signifies deficiency. In simplified Chinese it is called 肾亏, Traditional Chinese 腎虧, and in pinyin Shènkuī.

Shenkui or shen-k'uei is one of several Chinese culture-bound syndromes locally ascribed to loss (or fear of loss) of Yang (Chinese: 陽) . In Traditional Chinese Medicine, Shenkui is believed to result from a deficiency in yang, obtained through the loss of semen. Semen is believed to be "lost" through excessive sexual activity or masturbation, nocturnal emissions, "white urine" which is believed to contain semen, or other mechanisms. Symptoms within the Chinese diagnostic system include dizziness, backache, tiredness, weakness, insomnia, frequent dreams, and complaints of sexual dysfunction (such as premature ejaculation or impotence). From an ethnopsychiatric perspective, additional symptoms are preoccupation with sexual performance, potential semen loss, and bodily complaints which may be taken as symptoms of lost yang.

Losing semen reduces Yang, causing an unbalance in the body. Nocturnal emissions, too much intercourse, and masturbation resulting in ejaculation lower the levels of semen, causing loss of Yang. Somatic symptoms may include body soreness, aches, lack of energy, fatigue, and possibly problems in sexual performance.

A person suffering form Shenkui may endure body aches, dizziness, tiredness, inability to sleep, and sexual dysfunction, all for which no physical cause can explain.

The passing of semen too often is avoided because it is believed to be crucial to a person’s health and safety. It is believed to be life-threatening if too much semen is lost.

"Chinese martial artists that remained celibate through years and years of extensive training were believed to be most powerful, therefore maintaining the power of one’s vital essence."

A lallation (also called cambia-letras or troca-letra, "letter changer", in Latin American countries) is an imperfect enunciation of the letter "L", in which it sounds like "R" (or vice versa), as frequently found in infantile speech.

The speech pattern has been particularly associated with the use of the Portuguese, Spanish and English languages by Chinese, Korean, and Japanese people. The use of lallation has thus been a common feature of Western stereotypes of East Asian people. It is also common among English-speakers in parts of East Africa.

The first signs of poisoning suggest an allergic reaction with the following symptoms:

- facial flushing/sweating

- burning-peppery taste sensations in the mouth and throat

- dizziness

- nausea

- headache

- tachycardia

- cold-like symptoms

Yunnan sudden death syndrome is a label used to define unexplained cases of cardiac arrest, which afflicted significant numbers of rural villagers in Yunnan province, in southwest China. Cases occurred almost always during the midsummer rainy season (from June to August), at an altitude of . The cause turned out to be a mushroom now blamed for an estimated 400 deaths in the past three decades.

The mysterious fatalities were recorded for decades before researchers from the Chinese Center for Disease Control and Prevention isolated a significant factor common in every case: a tiny unknown mushroom which was unintentionally gathered and consumed during wild mushroom harvests in the region. Previously the syndrome was thought to be caused by Keshan disease, caused by the Coxsackie virus.

The mushroom, "Trogia venenata", is also known as 'Little White'. It has been determined that families collecting fungi to sell have been eating these Little White mushrooms as they have no commercial value. Three amino acids present in the mushrooms have been shown to be toxic. The mushrooms have also been shown to contain very high quantities of barium, and it may be that some of the deaths are simply from barium poisoning.

In the hours before death, about two-thirds of the victims had such symptoms as nausea, dizziness, heart palpitations, seizures and fatigue.

However, in December 2012 it was announced that Dr Xu Jianping (徐建平) has been collecting samples of "Trogia venenata" in Yunnan for the past three years, and his research now shows that barium levels in the wild mushroom are no higher than those of common foods such as poultry and fish. Nonetheless, it appears the mushroom will still likely play a role. Since publication of the widely circulated 2010 "Science" article, no instances of Yunnan sudden death syndrome have been reported.

The above symptoms can advance to:

- facial rash (intense itching may accompany the rash.)

- torso or body rash: The rash associated with scombroid poisoning is a form of urticaria, but most commonly does not include wheals (patchy areas of skin-swelling also known as hives) that may be seen in true allergies.

- edema (this is generalized if it occurs at all)

- short-term diarrhea

- abdominal cramps

Koro is a culture-specific syndrome delusional disorder in which an individual has an overpowering belief that one's genitalia are retracting and will disappear, despite the lack of any true longstanding changes to the genitals. Koro is also known as shrinking penis, and it is listed in the "Diagnostic and Statistical Manual of Mental Disorders". The syndrome occurs worldwide, and mass hysteria of genital-shrinkage anxiety has a history in Africa, Asia, and Europe. In the United States and Europe, the syndrome is commonly known as genital retraction syndrome. The condition can be diagnosed through psychological assessment along with physical examination to rule out genuine disorders of the genitalia that could be causing true retraction.

Most patients report acute anxiety attacks due to perceived genital retraction and/or genital shrinkage, despite a lack of any objectively visible biological changes in the genitalia that are longstanding. "Longstanding" refers to changes that are sustained over a significant period and do not appear reversible, unlike the effect of cold temperatures on some genital regions that cause retraction. These changes may trigger a koro attack when observed, although the effects of cold temperatures are objectively reversible. According to literature, episodes usually last several hours, though the duration may be as long as two days. There are cases in which koro symptoms persist for years in a chronic state, indicating a potential co-morbidity with body dysmorphic disorder. In addition to retraction, other symptoms include a perception of alteration of penis shape and loss of penile muscle tone. In cases when sufferers have no perception of retraction, some patients may complain of genital paraesthesia or genital shortening. Among females, the cardinal symptom is nipple retraction in the breast, generally into the breast as a whole.

Psychological components of koro anxiety include fear of impending death, penile dissolution and loss of sexual power. Feelings of impending death along with retraction and perceived spermatorrhea has a strong cultural link with Chinese traditional beliefs. This is demonstrated by the fact that Asians generally believe koro symptoms are fatal, unlike most patients in the West. Other ideational themes are intra-abdominal organ shrinkage, sex change to female or eunuch, non-specific physical danger, urinary obstruction, sterility, impending madness, spirit possession and a feeling of being bewitched.

Extremely anxious sufferers and their family members may resort to physical methods to prevent the believed retraction of the penis. A man may perform manual or mechanical penile traction, or "anchoring" by a loop of string or some clamping device. Similarly, a woman may be seen grabbing her own breast, pulling her nipple, or even having iron pins inserted into the nipple. Physical injury may occur from these attempts. These forceful attempts often lead to injuries, even death.

Patients that present with CARASIL usually experience neurological abnormalities by their 20s or 30s and strokes upon reaching their 40s. About 50% of affected patients present with stroke, and most strokes experienced by patients are lacunar infarcts. Many patients experience some form of mood changes, personality disorders, and or dementia. Alopecia, also known as hair loss, usually presents beginning in adolescence. The presence of spondylosis deformans and the onset of low back pain via the breakdown of intervertebral discs is also usually present. CARASIL is a degenerative disease, and most patients live only 10 years past symptom onset.

SJS usually begins with fever, sore throat, and fatigue, which is commonly misdiagnosed and therefore treated with antibiotics. SJS and TEN are often heralded by fever, sore throat, cough, and burning eyes for 1 to 3 days. Patients with SJS and TEN frequently experience burning pain of their skin at the start of disease. Ulcers and other lesions begin to appear in the mucous membranes, almost always in the mouth and lips, but also in the genital and anal regions. Those in the mouth are usually extremely painful and reduce the patient's ability to eat or drink. Conjunctivitis of the eyes occurs in about 30% of children who develop SJS. A rash of round lesions about an inch across arises on the face, trunk, arms and legs, and soles of the feet, but usually not the scalp.

In Chinese alchemy, elixir poisoning refers to the toxic effects from elixirs of immortality that contained metals and minerals such as mercury and arsenic. The official "Twenty-Four Histories" record numerous Chinese emperors, nobles, and officials who ironically died from taking elixirs in order to prolong their lifespans. The first emperor to die from elixir poisoning was likely Qin Shi Huang (d. 210 BCE) and the last was Yongzheng (d. 1735). Despite common knowledge that immortality potions could be deadly, fangshi and Daoist alchemists continued the elixir-making practice for two millennia.

In the brain, domoic acid especially damages the hippocampus and amygdaloid nucleus. It damages the neurons by activating AMPA and kainate receptors, causing an influx of calcium. Although calcium flowing into cells is a normal event, the uncontrolled increase of calcium causes the cell to degenerate. See reviews by Ramsdell (2007) and Pulido (2008).

Gastrointestinal symptoms can appear 24 hours after ingestion of affected molluscs. They may include vomiting, nausea, diarrhea, abdominal cramps and haemorrhagic gastritis. In more severe cases, neurological symptoms can take several hours or up to three days to develop. These include headache, dizziness, disorientation, vision disturbances, loss of short-term memory, motor weakness, seizures, profuse respiratory secretions, hiccups, unstable blood pressure, cardiac arrhythmia and coma.

People poisoned with very high doses of the toxin or displaying risk factors such as old age and renal failure can die. Death has occurred in 4 of 107 confirmed cases. In a few cases, permanent sequelae included short-term memory loss and peripheral polyneuropathy.

There is no known antidote available for domoic acid, so if symptoms fit the description, it is advised to go quickly to a hospital. Cooking or freezing affected fish or shellfish tissue does not lessen the toxicity.

New research has found that domoic acid is a heat-resistant and very stable toxin which can damage kidneys at concentrations that are 100 times lower than what causes neurological effects.

The exact nature of the poison is still unclear. In the U.S. outbreak, the source of the fish was traced by the Centers for Disease Control and Prevention, and studies of other fish from the same sources showed a hexane-soluble (and hence non-polar lipid) substance that induced similar symptoms in mice; other food-borne poisons commonly found in fish could not be detected. It cannot be inactivated by cooking, as all six CDC cases had consumed cooked or fried fish. Palytoxin has been proposed as a disease model. It has also been suggested that the toxin may have thiaminase activity (i.e. it degrades thiamine, also known as vitamin B1).

It was first described in 1924 in the vicinity of Königsberg, Germany (now Kaliningrad, Russia) on the Baltic coast, in people staying around the northern part of the Vistula Lagoon (German: "Frisches Haff").

Over the subsequent fifteen years, about 1000 cases were reported in people, birds and cats, usually in the summer and fall, and a link was made with the consumption of fish (burbot, eel and pike). Since that time, only occasional reports have appeared of the condition, mostly from the Soviet Union and Germany.

In 1997, six cases of Haff disease were reported in California and Missouri, all after the consumption of buffalo fish ("Ictiobus cyprinellus").

In July and August 2010, dozens of people contracted rhabdomyolysis after eating "Procambarus clarkii" in Nanjing, China. A month later, the Chinese authorities claimed they were victims of Haff disease.

An outbreak was reported in Brooklyn, New York on 18 November 2011, when two household members were stricken by the syndrome after eating buffalo fish. On February 4, 2014 two cases of Haff Disease were reported in Cook County, Illinois following the consumption of buffalo fish.

A group from Brazil has recently identified a Haff Disease outbreak in Bahia state with 71 cases identified.

Zhu Ling (, born 1973) is best known as the victim of an unsolved 1995 thallium poisoning case in Beijing, China. Her symptoms were posted to the Internet via a Usenet newsgroup by her friend from Peking University, Bei Zhicheng and were subsequently proven to be caused by thallium poisoning. Her case was then reviewed by physicians in many different countries who examined her symptoms and made suggestions as to diagnoses and treatment. This effort was recognized as the first large scale tele-medicine trial. Her life was ultimately saved, but she suffered serious neurological damage and permanent physical impairment.

This case drew great attention in the Chinese media, because the victim and the suspect were living in the same dormitory in the most prestigious university of China, and the case was never solved. Internet discussion of the crime has continued since then and became a hot topic on major online Chinese communities very frequently as a high-profile cold case.

Stevens–Johnson syndrome (SJS) is a milder form of toxic epidermal necrolysis (TEN). These conditions were first recognised in 1922. A classification first published in 1993, that has been adopted as a consensus definition, identifies Stevens–Johnson syndrome, toxic epidermal necrolysis, and SJS/TEN overlap. All three are part of a spectrum of severe cutaneous reactions (SCAR) which affect skin and mucous membranes. The distinction between SJS, SJS/TEN overlap, and TEN is based on the type of lesions and the amount of the body surface area with blisters and erosions. It is agreed that the most reliable method to classify EM, SJS, and TEN is based on lesion morphology and extent of epidermal detachment. Blisters and erosions cover between 3% and 10% of the body in SJS, 11–30% in SJS/TEN overlap, and over 30% in TEN. The skin pattern most commonly associated with SJS is widespread, often joined or touching (confluent), papuric spots (macules) or flat small blisters or large blisters which may also join together. These occur primarily on the torso.

SJS, TEN, and SJS/TEN overlap can be mistaken for erythema multiforme. Erythema multiforme, which is also within the SCAR spectrum, differs in clinical pattern and etiology. Although both SJS and TEN can also be caused by infections, they are most often adverse effects of medications.

Alcohol flush reaction is a condition in which an individual develops flushes or blotches associated with erythema on the face, neck, shoulders, and in some cases, the entire body after consuming alcoholic beverages. The reaction is the result of an accumulation of acetaldehyde, a metabolic byproduct of the catabolic metabolism of alcohol, and is caused by an acetaldehyde dehydrogenase deficiency.

This syndrome has been associated with an increased risk of esophageal cancer in those who drink. It has also been associated with lower than average rates of alcoholism, possibly due to its association with adverse effects after drinking alcohol.

Approximately 36% of East Asians (Japanese, Koreans, Vietnamese and Chinese) show characteristic physiological responses to drinking alcohol that includes facial flushing, nausea, headaches and tachycardia.

Foreign accent syndrome is a rare medical condition in which patients develop speech patterns that are perceived as a foreign accent that is different from their native accent, without having acquired it in the perceived accent's place of origin.

Foreign accent syndrome usually results from a stroke, but can also develop from head trauma, migraines or developmental problems. The condition was first reported in 1907, and between 1941 and 2009 there were 62 recorded cases.

Its symptoms result from distorted articulatory planning and coordination processes and although popular news articles commonly attempt to identify the closest regional accent, speakers suffering from foreign accent syndrome acquire neither a specific foreign accent nor any additional fluency in a foreign language. Despite an unconfirmed news report in 2010 that a Croatian speaker had gained the ability to speak fluent German after emergence from a coma, there has been no verified case where a patient's foreign language skills have improved after a brain injury. There have been a few reported cases of children and siblings picking up the new accent from someone with foreign accent syndrome.

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), is an inherited disease with symptoms of stroke, hair loss, and low back pain. The disease is rare and has only been diagnosed in about 50 patients, mostly of Japanese descent but few of Chinese and Spanish descent. There is currently no cure for CARASIL.

Individuals who experience the alcohol flushing reaction may be less prone to alcoholism. Disulfiram, a drug sometimes given as treatment for alcoholism, works by inhibiting acetaldehyde dehydrogenase, causing a five to tenfold increase in the concentration of acetaldehyde in the body. The resulting irritating flushing reaction tends to discourage affected individuals from drinking.

For measuring the level of flush reaction to alcohol, the most accurate method is to determine the level of acetaldehyde in the blood stream. This can be measured through both a breathalyzer test or a blood test. Additionally, measuring the amount of alcohol metabolizing enzymes alcohol dehydrogenases and aldehyde dehydrogenase through genetic testing can predict the amount of reaction that one would have. More crude measurements can be made through measuring the amount of redness in the face of an individual after consuming alcohol. Computer and phone applications can be used to standardize this measurement.

Other effects include "nausea, headache and general physical discomfort".

Many cases of alcohol-induced respiratory reactions, which involve rhinitis and worsening of asthma, develop within 1–60 minutes of drinking alcohol and are due to the same causes as flush reactions.

Since this syndrome is very rare, it takes a multidisciplinary team to evaluate the syndrome and diagnose it, including speech-language pathologists, neurolinguists, neurologists, neuropsychologists, and psychologists. In 2010, Verhoeven and Mariën identified several subtypes of Foreign Accent Syndrome. They described a neurogenic, developmental, psychogenic and mixed variant. Neurogenic FAS is the term used when FAS occurs after central nervous system damage. Developmental FAS is used when the accent is perceptible as of an early age, e.g. children who have always spoken with an accent. Psychogenic FAS is used when FAS is psychologically induced, associated with psychiatric disorder or clear psychiatric traits. The term mixed FAS is used when patients develop the disorder after neurological damage, but the accent change has such a profound impact on the self-perception and identity that they will modify or enhance the accent to make it fit with the new persona. Hence, there is a psychological component.

Diagnosis, up until today, is generally purely perceptually based. However, in order to find out what subtype the patient is suffering from, complementary investigations are necessary. This differentiation is necessary for the clinician to allow for correct therapeutic guidance. Psychological evaluations may be performed in order to rule out any psychiatric condition that may be causing the change in speech, as well as tests to assess reading, writing, and language comprehension in order to identify comorbid disorders often co-occurring with the disorder. One of the symptoms of this syndrome is that the patient moves their tongue or jaw differently while speaking, which creates a different sound, so a recording is done of the speech pattern in order to analyze it. Often images of the brain are taken with either MRI, CT, SPECT or PET scans. This is done in order to see if there is structural and or functional damage in the areas of the brain that control speech and/or rhythm and melody of speech. EEG is sometimes performed to investigate whether there are disturbances at the electrophysiological level.

Amnesic shellfish poisoning (ASP) is an illness caused by consumption of the marine biotoxin called domoic acid. This toxin is produced naturally by marine diatoms belonging to the genus "Pseudo-nitzschia" and the species "Nitzschia navis-varingica". When accumulated in high concentrations by shellfish during filter feeding, domoic acid can then be passed on to birds, marine mammals and humans via consumption of the contaminated shellfish.

Although human illness due to domoic acid has only been associated with shellfish, the toxin can bioaccumulate in many marine organisms that consume phytoplankton, such as anchovies, and sardines. Intoxication by domoic acid in non-human organisms is frequently referred to as domoic acid poisoning or DAP. In mammals, including humans, domoic acid acts as a neurotoxin, causing permanent short-term memory loss, brain damage, and death in severe cases.

Symptoms are often identified as being in one of three categories:

1. panic, discomfort, and uncontrolled spontaneous movement;

2. sensory problems, such as visual or auditory hallucination; and

3. irrational beliefs.

Somatic symptoms can include sensations and pain in head, chest and back, abdomen, limbs, or whole body; whereas, mental and emotional symptoms can include neurasthenia, affective disorder, self-consciousness, hallucination, and paranoia.

While the Chinese Society of Psychiatry prefers the term "qigong deviation", the American Psychiatric Association uses psychosis terminology. Some physicians believe that this disease can be categorized as a culture-bound syndrome, but this point is debated.

Tetraphobia (from Greek τετράς—"tetras", "four" and φόβος—"phobos", "fear") is the practice of avoiding instances of the number . It is a superstition most common in East Asian nations.