Start with the thing that sends most people here: you almost certainly can't feel it. Intestinal parasites don't produce a sensation of something moving — that feeling is nearly always ordinary gut activity. What does tell you something is the timing, two specific signs, and ultimately a test.
The "I can feel it moving" question
This is the single most common worry, and the answer is reassuring. Most intestinal parasites cause no sensation of movement at all. What people describe as wriggling or crawling is gas moving through the gut — something everyone experiences and rarely notices until they're looking for it.
Once you're worried about parasites, ordinary sensations get re-read as evidence. That's not foolishness; it's how attention works. But it isn't a symptom.
The two signs that genuinely mean something
Itching around the anus that's worse at night — especially in a child. This is the classic pinworm sign, and it's specific because the females travel to the skin after dark to lay eggs. It's extremely common and very treatable. More here.
Actually seeing something — thin white threads, or flat pale segments like grains of rice. Worth photographing. What the types look like.
Almost everything else on the internet's symptom lists — bloating, fatigue, cravings, brain fog — overlaps so heavily with ordinary conditions that it can't tell you anything on its own.
What it usually turns out to be
Before parasites, the common explanations are: IBS, food intolerance, SIBO, diet, stress, thyroid problems, low iron, or a plain viral infection. Every symptom in the parasite lists appears on those lists too. The side-by-side comparison is here.
How you actually find out
Stool test (ova and parasites) — the workhorse. A lab looks for parasites, eggs or their DNA. Doctors sometimes ask for samples across more than one day.
The tape test — specifically for pinworms; clear tape pressed to the skin first thing in the morning, before washing.
Blood tests — for certain parasites such as Toxoplasma, or to check for anemia from hookworm.
Important caveat: a single negative stool test doesn't fully clear it. Some parasites are shed on and off, so one sample can miss them. If your symptoms carry on after a negative result, that's a reason to go back and re-test — not a reason to start self-treating.
When to stop wondering and see someone
Blood in the stool, or black/tarry stools
Signs of dehydration — dizziness, very little urine, dry mouth, weakness
High fever or severe abdominal pain
Diarrhea lasting more than a few days, or relapsing over weeks
Unexplained weight loss
You're pregnant, immunocompromised, elderly — or it's a young child
Educational only: this page is general information, not medical advice or a diagnosis. Only a professional and a test can confirm or rule out a parasite.
Where next?
Visible
Worms in your stool
What the common types look like — and what's mistaken for one.
