Cascara Sagrada
Cascara sagrada bark in capsules, powder and tincture, from the tree Rhamnus purshiana. We explain how the forms differ, why this bark is for short-term use only, and what to check on the label before you buy.Read more →
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Cascara sagrada bark: forms, strength and short-term use
Cascara sagrada is the dried bark of Rhamnus purshiana, a small tree from the Pacific coast of North America. The Spanish name means sacred bark. The bark contains compounds called hydroxyanthracene derivatives, mostly cascarosides. Bacteria in the colon convert them before they become active, which is why nothing happens in the first few hours after a dose. In our range of herbal supplements you will find it as capsules, loose bark powder and tinctures.
The forms differ more than the labels suggest
Capsules are the most common choice in the UK, usually 350 mg to 450 mg of powdered bark, taken once in the evening. Powder and tea let you start lower, which helps if you react strongly to stimulant herbs. A tincture is bark extracted in alcohol and water. It is easy to dose drop by drop, though the taste stays bitter.
Three things are worth checking on any label:
- Bark weight per capsule, so you can compare products at all.
- Any standardisation to cascarosides, when the brand states it.
- Single ingredient or blend, because blends often add senna as well.
Here is the detail most product pages leave out. The strength of cascara is decided by its cascaroside content, not by the milligrams of bark. European quality standards require cascara bark to contain at least 8 percent hydroxyanthracene glycosides, and herbal medicines are dosed on that figure rather than on bark weight. Most food supplements print only the bark weight, so two capsules of 450 mg can behave differently. The bark also has to be dried and aged for months before use, never taken fresh.
How we choose cascara sagrada
We look at the form, at what the label really tells you about strength, and at whether the product fits a sensible routine. We prefer single-ingredient capsules and clearly labelled powders, because you keep control of the amount and can stop when you no longer need it. We are cautious with formulas that stack several stimulant herbs, since you cannot tell which part is doing what. We are also honest about the limit here: there is no approved European health claim for cascara, so we describe the plant and its traditional use, and nothing beyond that. Read how we select brands and products.
Who it suits and who should skip it
Cascara suits adults who want a herbal option for occasional use, not a daily habit. Guidance in the UK and Europe keeps this type of laxative to short-term use, up to about a week. Leave it out if you are pregnant or breastfeeding, under 12, or if you have a bowel condition, a blockage or stomach pain without a clear cause. Long use of stimulant laxatives can lower potassium, so ask a pharmacist first if you take diuretics or heart medication. If nothing has changed after three days, that is a signal to check in with a pharmacist rather than to raise the dose.
When irregularity keeps returning, a stronger stimulant is rarely the answer. Fibre, fluid and daily movement do more over weeks, and gentler options such as psyllium fibre can be used for longer stretches.
Our collection around digestion covers those calmer everyday choices. Cascara has its place: short, occasional, and with a clear end date.
Frequently asked questions
Cascara sagrada is the dried bark of Rhamnus purshiana, also listed as Frangula purshiana, a small tree from the Pacific coast of North America. Spanish settlers called it sacred bark, and the name stuck. The bark contains hydroxyanthracene derivatives, mainly cascarosides. Only the aged bark is used: it is dried and stored for months, because fresh bark is far too harsh on the stomach.
It has a long tradition of use for occasional, short-term bowel support, and that is also how European herbal medicine authorities describe it. In food supplements the situation is different: there is no approved European health claim for cascara, so we cannot promise you a result. What we can say is what the plant is, how it is dosed in practice, and why it is meant for a few days rather than for months.
Not immediately. The cascarosides in the bark travel to the colon first, where gut bacteria convert them into their active form. That is why cascara is traditionally taken once in the evening, with a full glass of water. Stimulant preparations of this type generally act six to twelve hours later. If you take it in the morning expecting a quick effect, you will be disappointed and tempted to take more, which is the wrong move.
It depends on how much control you want over the amount and how you feel about the taste.
| Form | Typical use | Best suited for |
|---|---|---|
| Capsules | 350 to 450 mg bark | Simple, no taste |
| Bark powder | Mixed in water or juice | Starting low |
| Tea | Steeped dried bark | Traditional use |
| Tincture | Drops in water | Fine adjustment |
Capsules are the practical default. Powder and tincture let you build up slowly, which matters if stimulant herbs tend to give you cramps.
Official dosing is based on the cascaroside content, not on the weight of the bark. The figures below come from the European herbal monograph for cascara bark used as a medicine. Food supplements usually state bark weight only, so follow the label of the product you have and start at the lower end.
| Point | Reference value |
|---|---|
| Adults, over 65s, over 12s | 10 to 30 mg, as cascaroside A |
| Maximum per day | 30 mg |
| Timing | Once daily, at night |
| Under 12 years | Not to be used |
| Duration | Up to 1 week |
Skip it if you are pregnant or breastfeeding, and do not give it to children under 12. It is also not suitable with an intestinal blockage, inflammatory bowel conditions such as Crohn's disease or ulcerative colitis, appendicitis, or stomach pain with no clear cause. Diarrhoea or loose stools are a reason to stop. If you take medication, in particular diuretics or heart medication, ask your pharmacist before you start, because potassium levels matter there.
No, and that is the honest answer even though it costs us sales. Preparations of this bark are meant for short-term use, up to about a week. NHS advice for shop-bought laxatives points the same way: stop once things improve, and speak to a doctor or pharmacist if three days bring no change. Repeated long use of stimulant laxatives can cause fluid loss and low potassium, which shows up as tiredness and muscle weakness.
Cascara and senna work by the same route. Both contain anthraquinone glycosides that stimulate the colon, and both are limited to short-term use. Users often describe cascara as the milder of the two, though that varies per person and per product, since strengths differ. Psyllium and Flaxseed work differently: they hold water and add bulk, act more slowly, and suit longer daily use. For a recurring pattern, that group is the more sensible starting point.
Because milligrams of bark say nothing about active content. European quality standards for cascara bark set a minimum of 8 percent hydroxyanthracene glycosides, of which at least 60 percent should be cascarosides. Real bark varies above that minimum, depending on origin, harvest and how long it was aged. Standardised extracts are declared on their glycoside content, plain bark powder usually is not. So treat a new product as new, and start at the lower end of its label.
