Last updated November 2026
Colonic hydrotherapy is one of the more talked-about natural health treatments, and one of the least understood. People in Nelson and Tasman often hear about it from a friend or a naturopath, then search to find out what actually happens, whether it is safe for them and how to prepare. This guide answers those questions plainly, including who should not have a colonic and when a GP visit should come first.
★View the Best Naturopaths in Nelson→What Colonic Hydrotherapy Is
Colonic hydrotherapy, also called colonic irrigation, colon hydrotherapy or simply a colonic, uses warm, filtered water to gently rinse the large intestine. In a modern clinic the water flows in and out through a closed system, so the session is private and there is no odour. The aim is to soften and release built-up waste and gas from the bowel.
Practitioners and clients often describe feeling lighter and less bloated afterwards, and many use colonics alongside dietary changes or a gut health programme. It is worth knowing that the scientific evidence for wider health benefits is limited, so a good practitioner will present a colonic as one support among several rather than a cure for any condition.
What Happens During a Session
- A health check first. Expect questions about your digestion, medical history, medications and any surgery, so the practitioner can confirm a colonic is suitable.
- Privacy throughout. You change in private and stay covered with a towel or gown for the whole session.
- A small, lubricated nozzle is inserted a short way, connected to the closed system that controls the water temperature and flow.
- Gentle filling and release. Water flows in slowly, and waste leaves through a separate tube. The practitioner may massage the abdomen to help things along. Most sessions take around 45 minutes to an hour, including the consultation.
- Afterwards you can usually get on with your day. Some people feel tired or a little crampy for a few hours.
Who Should Avoid Colonics
Colonic hydrotherapy is not suitable for everyone. Talk to your doctor before booking, and tell the practitioner, if any of these apply:
- Pregnancy
- Crohn’s disease, ulcerative colitis or diverticulitis, especially during a flare
- Recent bowel or abdominal surgery
- Severe haemorrhoids, fissures or rectal bleeding
- Heart or kidney disease, or medications that affect fluid balance
- Bowel cancer, or a recent change in bowel habits that has not been checked
A colonic is never a substitute for medical investigation. If you have blood in your stools, ongoing changes in bowel habit, unexplained weight loss or persistent abdominal pain, see your GP first. The Gut Foundation’s guide to your options explains which bowel symptoms need checking and how.
How to Prepare and Look After Yourself Afterwards
- Eat lightly for a day beforehand, with plenty of vegetables and water, and skip a heavy meal in the two hours before your appointment.
- Avoid alcohol and large amounts of caffeine the day before and the day after.
- Drink water afterwards, and choose simple, easily digested food for the rest of the day.
- Ask your practitioner whether they recommend probiotic foods or supplements to support your gut bacteria after the session.
Questions to Ask Before You Book
- Is the practitioner trained and certified in colon hydrotherapy, and by which organisation?
- Does the clinic use a closed system with single-use nozzles and filtered water?
- Will there be a health consultation first, and will they turn you away if a colonic is not right for you?
- How does the colonic fit with the rest of your plan, such as diet, herbal support or gut testing?
Colonic Hydrotherapy with Thrive Therapies
Thrive Therapies is the practice of Shanti Smith, a naturopath, herbalist, reflexologist and I-ACT certified colon hydrotherapist with over two decades in holistic health care. She offers colonic hydrotherapy at her Golden Bay clinic, at Aroha Health Spa in Pōhara, using a closed system with purified, body-temperature water. Shanti sees clients for naturopathy, herbal medicine and reflexology at 128 Hardy Street in Nelson as well, so a colonic can sit within a wider gut health plan. You can read more about her training and approach before you book.
