This article is for general information only and is not medical advice. If you think you have an infection, speak to a pharmacist or your GP.
The short answer
You cannot reliably tell from how you feel, or from what you see in the toilet. There is no good-quality evidence that herbal parasite cleanses clear infections in people, and the signs usually described as proof have other, more likely explanations. The only dependable way to know whether you have a parasite, and whether it has gone, is a test arranged through your GP.
Why feeling better is not proof
The symptoms most often blamed on parasites online include bloating, wind, changes in your poo, tiredness, food cravings, skin rashes, poor sleep and teeth grinding. All of these are very common and have many possible causes, from diet and stress to conditions such as irritable bowel syndrome, coeliac disease or iron deficiency.
They can improve during a cleanse for reasons that have nothing to do with parasites:
- Your diet changes. Most cleanse routines cut out alcohol, sugar and processed food, which is enough to ease bloating and improve energy for many people.
- Symptoms come and go on their own. People tend to start a cleanse when they feel at their worst, so some improvement afterwards is likely whatever they do.
- Expectation plays a part. When you have invested time and money in something, you are more likely to notice the good days.
Feeling worse is not proof either. Tiredness, cramps or loose stools during a cleanse are often described as a sign that parasites are dying off, but they can simply be side effects of the herbs. Some cleanse products also contain laxative ingredients.
What about things you see in the toilet?
This is the sign people find most convincing, and it is also unreliable. Strands of mucus, undigested vegetable fibre and the gel formed by fibre supplements are easily mistaken for worms, especially when you are looking out for them.
Real worms tend to look quite specific. The NHS describes threadworms as small white worms that look like pieces of thread. Other worms are much larger. If you see something you think is a worm or a piece of worm, do not rely on your own judgement or on photos online. Tell your GP, who can arrange for a poo sample to be tested.
Some parasites, such as giardia, are microscopic, so you would never see them at all.
How infections are actually confirmed and treated
- Threadworms can usually be recognised from the symptoms. A pharmacist can recommend medicine, which is used together with strict hygiene. See the NHS threadworms page.
- Other worms are confirmed with a poo sample. A GP will prescribe medicine that you take for 1 to 3 days. See the NHS page on worms in humans.
- Giardiasis is confirmed with a poo sample and treated with antibiotics. Symptoms usually stop within about a week. See the NHS giardiasis page.
We go through the timings in how long does it take to get rid of parasites?
A more useful way to track your symptoms
Keeping notes is still worthwhile, just for a different reason. A short daily record of your symptoms, what you ate and any supplements or medicines you took gives your GP something concrete to work with, and makes it much easier to spot patterns. Take it with you to your appointment.
See your GP rather than continuing a cleanse if you:
- find a large worm, a piece of worm or worm eggs in your poo
- have sickness, diarrhoea or a stomach ache for longer than 2 weeks
- are losing weight for no reason
- have a red, itchy, worm-shaped rash on your skin
Contact your GP or NHS 111 urgently if you have diarrhoea that has lasted more than 7 days, is getting worse quickly, or has blood in it.