Colonic hydrotherapy — also called colonic irrigation or colonics — is a professionally administered treatment that gently introduces warm, filtered water into the large intestine via the rectum. The aim is to help soften and ease the passage of accumulated waste, gas, and mucus, supporting better digestive function and a feeling of lightness. At Phenomenal Colonics, Marijke uses individually blended organic herbal preparations for each client alongside the water, tailored to your specific constitution and condition.
A closed system uses a sealed speculum through which water enters and waste is carried away through a closed pipe — entirely hygienic, with no odour. A therapist remains in the room throughout to assist with abdominal massage and monitor pressure. An open system uses a smaller tube inserted into the rectum; water flows in continuously and waste releases naturally around it into a specialist basin. Marijke uses the open gravity system, which she manually controls throughout your session — she remains present at all times, providing abdominal massage and adjusting the treatment to how your body is responding. Both systems use single-use disposable equipment.
Very much so, particularly in London. Phenomenal Colonics has been established for over 25 years and Marijke’s 40+ five-star Google reviews are almost entirely from personal recommendation. Demand has grown significantly as awareness of gut health and its connection to overall wellbeing has increased.
Women make up the majority of clients, often because they tend to be more proactive about health. That said, many men find colonics extremely beneficial once they try it — and tend to become regular clients. There is nothing gender-specific about the treatment itself.
You do not need to fast. In the two hours before your session, avoid eating a large meal or drinking excessive liquids. In the days beforehand, staying well-hydrated with water or herbal teas is helpful, and it is worth reducing alcohol, heavy animal proteins, and refined carbohydrates for 24 hours before your appointment. Marijke will send you preparation guidance when you book your colonic and is happy to answer any questions beforehand.
The treatment should not be painful. You may feel a mild sensation of fullness or a natural urge as the water enters — this is normal and most clients settle into the treatment within the first few minutes, often finding it more relaxing than they expected. If there is significant gas, there may be some mild cramping, but this passes quickly as the colon releases. Marijke provides gentle abdominal massage throughout the session and her individually blended herbal preparation is specifically designed to support comfort as well as effectiveness. If at any point you feel uncomfortable, just let Marijke know.
It is completely normal to feel nervous or self-conscious before a first session — and very common for clients to say afterwards that it was nothing like they feared. Marijke has been practising for over 25 years and is experienced at putting new clients at ease. You remain covered throughout the treatment, dignity is maintained at all times, and the open gravity system is clean and odour-free.
The active treatment time is around 45 minutes but allow approximately an hour for the full appointment, including changing and bathroom time. For a first session, Marijke will take time at the start to discuss your health history, digestive symptoms, and lifestyle — so allow a little longer for your initial visit.
Most clients come because something doesn’t feel quite right — persistent bloating, sluggishness, clothes fitting tightly around the middle, or low energy that doesn’t seem to improve. Others come as part of a broader health maintenance routine. Marijke will always discuss your reasons and health picture before your first session.
Marijke uses single-use disposable equipment for every treatment. The water is filtered and purified before use. She also incorporates an individually blended organic herbal preparation — certified Demeter organic — into each session, which is chosen specifically for your individual needs.
Common contributing factors include low fluid intake, a low-fibre diet, insufficient exercise, stress, candida overgrowth, and parasites. Diet plays a significant role — dairy, fried foods, excess sugar, alcohol, and fizzy drinks can all affect how the bowel functions over time. Marijke will take a full picture of your health and lifestyle and can advise on dietary adjustments alongside treatment.
Good nutrition is only part of the picture. If the bowel isn’t absorbing efficiently, even high-quality food and supplements may not be working as well as they could. Clearing the digestive system can help everything else function more effectively. During an iridology consultation, the bowel is always the first thing Marijke examines — digestive health underpins a great deal of how we feel day to day.
The water works within the large intestine only. However, clearing the large intestine can encourage residue in the small intestine to move through as well. This is one of the reasons Marijke often recommends a follow-up session — the second treatment tends to build meaningfully on the progress of the first.
Most clients feel lighter, clearer, and more comfortable. Some feel pleasantly relaxed or a little tired as the body processes the treatment — both are normal responses. You can return to your usual activities right away. Clients with significant congestion or candida may notice more gradual improvement over a series of sessions, which Marijke will discuss with you.
Keep it light and easy to digest. Marijke typically recommends fresh fruit salad in warmer months and a simple vegetable or miso soup in cooler months. Avoid heavy, spicy, or processed food for the rest of the day. She will give you specific aftercare guidance based on your individual treatment.
For most clients, yes — particularly once the specific dietary or lifestyle triggers contributing to the bloating are identified. Marijke takes time to understand your individual picture and can advise on both treatment and dietary adjustments that would support the best outcome.
This is a common concern and worth addressing clearly. The water used in a colonic does not destroy beneficial bacteria. The microbiome is embedded in the mucosal lining of the gut and is resilient — removing accumulated waste actually creates a cleaner environment for beneficial bacteria to function in. That said, a colonic is an excellent opportunity to actively replenish your gut flora. Marijke may recommend a course of probiotics after your session, which she can discuss at the time. None of this is obligatory.
The most common culprits are sugar, alcohol, antibiotics — including those present in intensively farmed meat and dairy — stress, and poor sleep. Marijke takes a holistic view of gut health and will discuss any relevant factors during your consultation.
Any immediate change in weight after a colonic reflects the removal of accumulated waste and water — not fat loss. Many clients notice a reduction in bloating and feel their stomach is flatter and more comfortable. Colonic hydrotherapy is a digestive health treatment and should not be positioned as a weight-loss solution, but it can be a useful part of a broader approach to feeling healthier in your body.
One session will not completely empty the colon, and results build over time. For most new clients, Marijke recommends starting with up to three sessions reasonably close together — this allows each treatment to build on the previous one and gives the digestive system time to reset properly. After that, clients follow up as needed: some come seasonally, others more regularly. Marijke will advise based on how you respond.
No — the aim is quite the opposite. As your colon learns to function more effectively, natural peristalsis is restored and improved. Alongside dietary and lifestyle changes, the goal is for your bowel to maintain its function well independently. Think of it as a reset rather than a dependency.
When performed by a certified, trained practitioner using modern equipment, colonic hydrotherapy is safe for the vast majority of people. Marijke is ARCH accredited — ARCH is the only colon hydrotherapy association regulated by the government-backed CNHC — and has been practising for over 25 years. All water is filtered and temperature-regulated. Single-use disposable equipment is used for every session.
Yes — it is safe to have a colonic during menstruation and some clients find it helpful for period-related bloating and discomfort. You will need to remove any tampon or menstrual cup before the treatment begins and bring a fresh one to use afterwards.
No. Colonic hydrotherapy is not recommended at any stage of pregnancy. Professional associations including ARCH advise against it, as the treatment stimulates the abdominal region and smooth muscle tissue. If you are pregnant and have questions about digestive health, please speak with your midwife or GP.
Colonic hydrotherapy is not appropriate for everyone. You should not have a treatment if you have active diverticulitis, Crohn’s disease, ulcerative colitis, severe haemorrhoids, severe anaemia, kidney disease, or if you have had recent abdominal or bowel surgery. If you have an underlying medical condition, please consult your GP before booking. Marijke is also happy to discuss any concerns before your first appointment — just get in touch.
A note on health claims Colonic hydrotherapy is a complementary therapy and is not a substitute for medical treatment. The information on this page reflects Marijke’s professional experience and is intended for general guidance only. If you have any medical concerns, always consult your GP or healthcare provider.
