Why preparation matters
A colonoscopy works by the camera looking directly at the lining of your bowel. If there's residual material in there, it blocks the view — and small polyps (the ones we most want to catch) can easily hide behind it. Research shows that poor preparation can triple the miss rate for polyps. If the preparation isn't adequate on the day, the procedure will almost certainly need to be repeated — which means another full day of preparation, another round of sedation, and another appointment. Nobody wants that.
The preparation is the least enjoyable part of the whole experience, but it genuinely makes a difference to the outcome. If you're unsure about anything in your instructions, please call Mr Nguyen's rooms on (03) 9816 3951. Don't guess. And if your bowel motions are still brown or cloudy when they should be clear, contact us before heading in — there may be options.
If you are Mr Nguyen's patient
Food: You can eat normally up until 6 hours before your admission time, then nothing to eat at all. Your procedure may be cancelled if you eat after this point — this is a safety rule for your sedation.
Clear fluids: You can drink clear fluids up until 2 hours before your admission time. Clear fluids include: water (still or sparkling), clear broth or Bonox, pulp-free juice, plain cordial or lemonade, plain jelly or ice blocks, orange or yellow Gatorade or Powerade (great for replacing electrolytes), and black tea or coffee with a small dash of milk. Avoid anything red, purple, or orange coloured — these pigments can stain the bowel lining and be confused with blood during your examination.
Medications: Keep taking all your regular medications as usual, with a small sip of water. Please don't chew gum on the day of your procedure.
Supplements: Stop all over-the-counter vitamins, minerals, and herbal supplements (including fish oil, glucosamine, and vitamin E) at least 5 days before your procedure. Iron supplements in particular should stop at least 3 days before — iron coats the bowel lining and can obscure the view significantly.
Blood thinners: If you take warfarin, rivaroxaban (Xarelto), apixaban (Eliquis), dabigatran (Pradaxa), or clopidogrel, please contact Mr Nguyen's rooms ahead of time for specific advice. These medications may need to be stopped temporarily or managed carefully around your procedure.
Diabetes medications: If you take oral or injectable diabetes medications (such as Metformin, Diamicron, Jardiance, or Forxiga), please stop these 2 days before your procedure. Do not stop insulin without speaking to us first — contact our rooms for personalised advice about how to adjust your doses.
Weight loss injections (GLP-1 medications like Ozempic or Wegovy): If you use semaglutide (Ozempic, Wegovy), liraglutide (Saxenda), dulaglutide (Trulicity), or a similar medication, please stick to clear fluids for the full 24 hours before your admission time. You don't need to stop the medication — just let our rooms know when you book.
Preparation timeline
5–3 days before — low-fibre diet
Switch to a low-fibre diet. This reduces the amount of undigested material in your bowel so the preparation solution can work more effectively. Avoid wholegrain bread, cereals, nuts, seeds, raw vegetables, salads, corn, mushrooms, legumes, and fruit with skin. Stick to white bread, white rice, cooked vegetables without skins, lean meat, fish, eggs, and plain dairy. It's not as restricted as it sounds once you get the hang of it.
Day before — clear fluids from 3pm, then first two preparation doses
You can continue with your white-food diet until 3pm, then switch to clear fluids only for the rest of the day. See the clear fluids list in the fasting box above — avoid anything red, purple, or orange coloured. Try to have about one glass of fluid every hour and keep drinking right up until bedtime.
Mr Nguyen's standard preparation is Picoprep, used as 3 sachets spread across two days — two sachets on the evening before and one on the morning of the procedure. This split approach produces noticeably better bowel cleansing than a single large dose, and higher polyp detection rates. Follow the mixing and timing in your downloaded preparation guide exactly. Stay close to a bathroom — the effects usually begin within 30 to 60 minutes, and you'll have frequent, watery motions for two to four hours. This is exactly what's supposed to happen.
Morning of procedure — third dose, then nothing by mouth
Take the third and final sachet early in the morning — typically around 5am for a morning procedure, so you'll need to set an early alarm. After your dose, continue sipping clear fluids until 2 hours before your admission time, then nothing at all to eat or drink. By the time you've finished, your motions should be running clear to pale yellow. Take your regular medications with a small sip of water. No chewing gum.
Please don't stop your preparation early just because things look clear down below — residue can still be sitting higher up in the colon even when the rectum seems clean. Complete the full prescribed dose as directed.
Preparation solutions and downloads
The preparation prescribed for you is chosen based on your medical history, kidney function, age, and the time of your procedure. All of these preparations are available from a pharmacy without a prescription. Download your specific instructions and take them with you when you go to collect it.
Mr Nguyen's usual preparation is Picoprep (sodium picosulphate), taken as 3 sachets split across two days. Download your instructions below.
A lower-volume option — two litres total, split across two doses — that may be offered as an alternative, particularly for older patients. Your specific dosing schedule will be in the guide provided by our rooms.
One of the lower-volume preparations available, taken as a split dose. Most patients find it produces good cleansing without requiring large volumes of liquid.
A larger-volume preparation — up to four litres — used in specific situations where the lower-volume options aren't suitable for you medically.
A more thorough preparation protocol prescribed when a previous colonoscopy preparation wasn't adequate, or when Mr Nguyen has specifically recommended it — including for patients with long-standing constipation. Please only follow this schedule if you've been directed to use it.
Practical tips and what to expect
Things usually start moving about one to three hours after your first dose. Your motions will become progressively watery — this is exactly what's supposed to happen, so don't be alarmed. Mild nausea is fairly common; chilling the solution and sipping slowly helps. Because of all the trips to the bathroom, the skin around the anus can become sore — apply a thin layer of Vaseline or a barrier cream (Sudocreme or Bepanthen work well) before you start, and reapply as needed. Use soft, moist wipes rather than dry toilet paper.
Making it more tolerable
- Refrigerate the solution beforehand — cold liquid is genuinely easier to get down.
- Drink through a straw — it bypasses more of the taste buds on the tip of the tongue.
- Clear your diary for the preparation evening — there's no way around spending time close to the bathroom.
- Keep sipping clear fluids between doses to stay hydrated — orange or yellow Gatorade or Powerade is a good choice for replacing electrolytes.
- Distract yourself — put on a film or podcast while you drink. It genuinely helps.
By the time you've finished, your motions should be running clear to pale yellow with no solid particles. If they're still brown or cloudy, please contact us or the endoscopy facility before heading in — don't just arrive and hope for the best. There may be options such as an additional dose, a later slot, or rescheduling. A colonoscopy through a poorly prepared bowel is likely to miss things, and it will need to be repeated. It's much better to flag it early.
Special circumstances
Chronic constipation: If you have long-standing constipation, please let Mr Nguyen's rooms know well in advance of your procedure date. You will likely need the extended preparation protocol, which gives things more time to work. Download the instructions from the preparations section above if you've been directed to follow it.
Kidney disease: Phosphate-based laxatives can be harmful if you have impaired kidney function and should be avoided. Polyethylene glycol preparations (such as Plenvu or Prepkit Orange) are generally safer for you. Please mention your kidney function when you book.
Heart failure or fluid retention: Large volumes of preparation fluid can worsen fluid retention if you have heart failure. A lower-volume preparation like Picoprep is usually preferred in this situation. Please discuss this with Mr Nguyen's rooms before you purchase your preparation kit.
Frequently asked questions
From 3pm the day before your colonoscopy, you're limited to clear fluids only — nothing opaque. That means no milk, cream, protein shakes, smoothies, or milk-based coffee drinks. A small dash of milk in your tea or coffee is acceptable before 3pm, but after that point it's clear fluids only. We know it's a long day.
Stop, wait about 30 minutes, and then try to continue at a slower pace. Chilling the solution and drinking through a straw can help it stay down. If you simply cannot keep the preparation down at all, call Mr Nguyen's rooms on (03) 9816 3951 for advice. Please don't skip the remaining dose without speaking to us first.
Please call us or the endoscopy facility and describe what you're seeing. The team can advise whether the preparation is adequate or whether you need an extra dose or a different approach. Don't just proceed if you're unsure — an inadequate preparation almost always means the procedure will need to be repeated, which is exactly what everyone wants to avoid.
Yes — the timing of both your diet and your preparation doses is adjusted for afternoon procedures. Your specific instruction sheet will cover this. Follow your own instructions rather than adapting the morning schedule — the two are quite different.
Learn more about this procedure — including what to expect, benefits, risks, and recovery.
Procedure details →Questions about your preparation?
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