Click here to read symptoms described in medical literature.

Other symptoms reported to this site:

Cravings for sweets/starchy foods (see Diet);
Food sensitivites - particularly to high carb foods, fruit and sweets.
Thick white/grey tongue coating;
Undigested food particles in stool;
Nervous and sensory disorders including inability to concentrate, depression, panic attacks. brain fog, sleep disturbances, depression and feelings of doom.
Fatigue.
Hot and cold sweats.

I have been diagnosed through Great Smokies Diagnostic laboratory in the US with 'many' blastocystis hominis....my symptoms are extreme fatigue and brain fog "
L. 19 March 03

"I have been suffering from the following symptoms over a period of approximately 8 months: flatulence, loose stools, dizziness, hot and cold sweats, neckache, elevated heartbeat, lower back pain, bloating, weakness, shakes, loss of appetite, cravings for sweet foods, feelings of death, general feeling of unwellness. January 2003 I diagnosed with Blastocystis Hominis infection after asking to have a stool test. I requested this test because a friend of my wife's had been suffering with similar symptoms and was found to have Intestinal Parasites."
March 03

"I have (been diagnosed with Blasto) and experienced abdominal pain and fatigue consistently".
A. 28 Feb. 03

"I am from the eastern USA. I have been suffering for the last eight months from general gastritis, excess amount of gas, belching, general weakness, abdominal pain and waking up from a sound sleep during the night with abdomen pain. The abdomen pain goes away with food. Sometimes I get spasms which also goes away taking some anti-spasmatic medicine."
H. Diagnosed with B.hominis, August 02

"I have an itchy bottom; incredibly poor digestion; excess gas and bloating; decreased physical capacity. it took a long time for me to be diagnosed, and i've been ill for the better part of a year. My doctor described B.Hominis as a "benign parasite" and said it couldn't possibly be causing my symptoms. I've been treated with flagyl, for 7 days but not much difference"
(Queensland man with Blasto., October 2005)

Medically documented symptoms:

Click here to read a complete of 19 symptomatic patients infected with Blastocystis hominis.
Association of Blastocystis hominis with signs and symptoms of human disease. D J Sheehan, et al. J Clin Microbiol. 1986 October; 24 (4): 548-550

Purged stools from 389 patients were evaluated microscopically for the presence of Blastocystis hominis. A total of five or more B. hominis cells per 40X field were observed in 43 patients (11%), and B. hominis was the only intestinal parasite present in 23 (6%) of these patients. Of the 23 patients, 19 had symptoms which included abdominal discomfort (15 patients), anorexia (10 patients), diarrhea (9 patients), and flatus (9 patients) . The remaining four patients were asymptomatic.

Two apparently healthy children from the same family were found to have moderate to heavy Blastocystis hominis in their stool samples whilst being investigated for intestinal symptoms:
sporadic, painless, rectal bleeding in one and persistent diarrhea in the other.
Blastocystis hominis in two children of one family
West Indian Med J 1990 Mar;39(1):57-8 . Bratt DE, Tikasingh ES.

We describe a unique case of severe Blastocystis hominis infection in an elderly man with severe dehydration, marked leukocytosis and hypoalbuminaemia after antibiotic treatment for right pneumonia. The patient recovered after treatment with metronidazole. This case presentation demonstrates the ability of B. hominis to induce severe gastrointestinal manifestations and general deterioration, particularly in light of the controversy surrounding its possible potential pathogenicity.
Severe Blastocystis hominis in an elderly man. J Infect 1996 Jul;33(1):57-9 Arch Intern Med 1988 May;148(5):1064

We describe the case of a ten year-old girl who was admitted to our hospital for diarrhea, abdominal pain and fever . The presence of B. hominis was demonstrated in her stools. The patient responded favourably to treatment with metronidazole. We feel that our observation is an additional support to recognition of B. hominis as a human pathogen.
Blastocystis hominis infection: a case report. Antonelli F et al. Minerva Pediatr 1996 Dec;48(12):571-3

The most usual complaint of blastocystis patients is of intense abdo. discomfort accompanied by pain. Diarrhea is not standard, and constipation is common. The symptoms gleaned from the literature include abdo. pain, discomfort, anorexia, bloating, cramps, diarrhea, constipate, alternating diarrhea and constipation, watery diarrhea, mucus diarrhea, vomiting, dehydration, sleeplessness, nausea, weight loss, inability to work, lassitude, dizziness, flatus, pruritus, and tenesmus.
Blood in the stool as well as excessive mucus and leukocytes have been reported. Moderate to severe eosinophilia is not uncommon and was reported in 8 of 19 patients in one study.
Blastocystis hominis - Past and Future. Clin. Micro. Reviews. Jan 1991 p. 61-79

Twenty-nine patients were asymptomatic (59%), and 20 had symptoms of bloating, flatulence, soft/loose stools, or constipation.
Blastocystis hominis in hospital employees. Am J Gastroenterol 1992 Jun;87(6):729-32

Of the 23 patients, 19 had symptoms which included abdominal discomfort (15 patients), anorexia (10 patients), diarrhea (9 patients), and flatus (9 patients).
Association of Blastocystis hominis with signs and symptoms of human disease.
J Clin Microbiol 1986 Oct;24(4):548-50

The most frequent symptomatology in patients with B. hominis only was: abdominal pains, pruritus, flatulence, malaise, anorexia and diarrhea. Only 14.9% did not present any symptoms at all.
Isolate resistance of Blastocystis hominis to metronidazole (Flagyl).
Trop Med Int Health 1999 Apr;4(4):274-7

The clinical picture of B. hominis consists of non specific abdominal pain, watery diarrhea, anorexia, vomiting and weight loss. Rarely, a more invasive form of the disease with rectal bleeding can occur.
Blastocystis hominis infection: a case report. Minerva Pediatr 1996 Dec;48(12):571-3

A study at the Children's Hospital of Pittsburgh in the USA in 1993 found that 85% of children infected with Blasto. experienced gastrointestinal symptoms, including abdominal pain, diarrhoea, vomiting, and weight loss. Seventy-five percent of these children had been exposed to well water or had travelled to third-world countries.
Prevalence and characteristics of Blastocystis hominis infection in children. Clin Pediatr (Phila) 1993 Feb;32(2):91-6

A 9 month survey carried out on 39 children in a hospital in Kuwait found abdo. pain or discomfort with or without diarhoea was present in 32 children. Only three of the children were diagnosed with other parasites. Fourteen cases diagnosed as acute experienced cramp-like diarrhoea, watery diarrrhoea and vomiting.
J Trop Med Hyg 1991 Apr;94(2):118-22. Blastocystis hominis infection in children.

A study of 49 hospital employees in New York infected with Blastocystis hominis - 59% were asymptomatic. The remainig 41% experienced bloating, flatulence, soft/loose stools, or constipation.
Am J. Gastroenterology 1992 June;87(6):729-32. Blastocystis hominis in hospital employees.

Fifty-two patients at a teaching hospital in the US found without concomitant parasitic infection or bacterial pathogens in stool experienced gastrointestinal symptoms. The highest reported symptom was abdominal pain, diarrhea and five patients experienced vomiting. In 50 of these patients Blasto only was identified in stool samples.
J Clin Gastroenterol 1990 Oct;12(5):525-32. Frequency of recovery of Blastocystis hominis in clinical practice.

Of 143 at a Canadian hospital where B.hominis was the only parasite found:
19 patients were asymptomatic
15 had symptoms of acute gastroenteritis
21 had chronic gastroenteritis
One hundred and thirty of these patients reported watery diarrhoea, abdo. pain and gas.
J Clin Microbiol 1990 Jan;28(1):116-21. Epidemiology and pathogenicity of Blastocystis hominis.

Symptoms of B. hominis in a hospital in Saudi Arabia found the most common symptoms were abdominal pain (87.9%), constipation (32.2%), diarrhea (23.4%), alternating diarrhea and constipation (14.5%), vomiting (12.5%), and fatigue (10.5%).
Clinical significance of Blastocystis hominis. Qadri SM, al-Okaili GA, al-Dayel F. Department of Pathology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia



see also Other illnesses and Medical Mismanagement