Being handed a little plastic pot and asked for a poo sample is one of those moments nobody prepares you for. The good news is that how to do a stool sample comes down to three things: catch it before it touches the water, scoop a small amount into the pot, and get it back quickly. Here is the step-by-step, plus the mistakes to avoid.
To do a stool sample, pee first, then catch your poo on something clean, such as cling film stretched over the toilet rim or a disposable container. Use the scoop in the lid to fill the pot to the level your instructions give, label it, seal it in a bag and hand it in as soon as you can.
What you need before you start
Your GP surgery will usually give you a sterile pot with a scoop in the lid, plus a label or form. At home, you will also need something to catch the poo and a plastic bag [1]. Our stool health FAQ answers the questions people are too embarrassed to ask.
For catching, the NHS suggests a clean disposable container in the toilet, or newspaper or cling film spread over the rim [1]. Folded toilet paper works too. The aim is that the poo never touches the water. It also helps to note what it looked like on the Bristol Stool Chart, in case your GP asks.
How to collect a stool sample at home, step by step
- Write your name, date of birth and the date on the pot label, and fill in any form you were given.
- If you need to pee, do it first so the sample is not mixed with urine [1].
- Set up your catch over or in the toilet.
- Do your poo onto it as normal.
- Use the scoop to transfer some poo into the pot. How much stool is needed? Fill only to the level your instructions state; for example, NHS guidance suggests just under halfway, while some local trusts ask for about a third [1][2].
- Screw the lid on, tip the rest into the toilet, bin everything else in a tied bag, wash your hands and seal the pot in its specimen bag.
How to store a stool sample
Some components of a stool sample can change over time, which is why it should be stored and returned according to the test instructions [1]. If you cannot hand it in straight away, follow the storage instructions from your GP surgery or laboratory. Some NHS services advise keeping it in the fridge in a sealed bag for up to 24 hours, but requirements vary by test [2]. Do not freeze it unless your instructions specifically tell you to, and if you have recently taken antibiotics, mention it when you hand it in.
| Common mistake | Why it matters | Easy fix |
|---|---|---|
| Poo touches toilet water | Can contaminate the sample | Catch it before it lands |
| Pee mixed in | May affect results [1] | Pee first, then collect |
| Overfilling the pot | Can leak in transit | Fill only to the stated level |
| Missing label details | The lab needs to match it to you | Label before you start |
| Leaving it too long | Some components can change [1] | Follow your kit's storage instructions [2] |
What is a stool sample test for?
A GP may ask for a sample if you have symptoms such as diarrhoea, constipation, tummy pain or blood in your poo [1]. Labs can look for infections, hidden blood and markers of inflammation. Our explainers on mucus in stool and loose stools explain common reasons for testing.
A home bowel cancer screening kit is different. In England, the NHS posts a test to everyone aged 50 to 74 every 2 years, and it uses a small stick rather than a scoop [3]. Follow that kit's own instructions. Bowel cancer awareness is worth a read if your kit has just arrived.
Can I take a stool sample from the toilet water?
It is best avoided. Toilet water can dilute or contaminate the sample, which may affect the result [1]. If it lands in the water, ask your surgery whether to try again.
What if I have diarrhoea?
If you have diarrhoea, follow the collection instructions from your GP or laboratory. A liquid sample can usually be collected directly into a clean container, such as a disposable food tub, before being transferred to the specimen pot.
Before the day, ask your surgery where and by what time to drop the sample off, and whether it can go in the fridge overnight. If you are unsure whether your habits are typical anyway, our digestion self-check is a calm place to start. Put cling film and a spare bag in the bathroom in advance, and label the pot while your hands are clean.
References
- NHS. How to collect a sample of poo (stool sample). https://www.nhs.uk/common-health-questions/infections/how-should-i-collect-and-store-a-stool-faeces-sample/
- York and Scarborough Teaching Hospitals NHS Foundation Trust. Collecting a stool (faeces) sample. Patient information leaflet. https://yorkhospitals.nhs.uk/seecmsfile/?id=2436
- GOV.UK. Bowel cancer screening: programme overview. https://www.gov.uk/guidance/bowel-cancer-screening-programme-overview
This content is for informational purposes only and does not constitute medical advice. If you have concerns about your digestive health, please speak to a qualified healthcare professional.
