How to Brew Horsetail Tea (Cola de Caballo) the Right Way

July 8, 2026

Cola de caballo, or horsetail, is one of those herbs you'll find in almost every Peruvian kitchen cupboard and just about every market stall in Lima. The plant looks like a bottle brush and it's genuinely ancient, older than most flowering plants on earth. People in Peru drink it for kidney and urinary support, and the bags on our shelves get marketed as a "hair and skin elixir" because of the mineral it's known for: silica.

Here's the honest part before we get to the kettle. The research on horsetail is thin. There are small human studies on its mild diuretic effect and some lab work on silica and connective tissue, but nothing that would let anyone promise you thicker hair or clearer skin. What we can help with is the brewing, because a lot of people make horsetail badly and then wonder why it tastes like pond water. Done right, it's a clean, grassy, slightly mineral cup.

What you'll need

One tea bag, or about one to two teaspoons of loose horsetail if you're using the dried herb. Fresh water, ideally filtered. A mug you can cover. That's the whole list. If you want to soften the grassy edge, keep a slice of lemon or a little honey nearby, but taste it plain first.

Step one: get the water hot, not boiling hard

Bring your water up to around 200 to 205 degrees Fahrenheit. That's just under a rolling boil, the point where you see small bubbles breaking the surface. If you let it hit a hard boil, wait about 30 seconds before pouring. Screaming-hot water pulls out more of the bitter, astringent compounds and less of what you actually want. This isn't fussiness. It's the single change that fixes most people's horsetail.

Step two: pour and cover

Pour roughly 8 ounces of water over the bag or loose herb, then put a saucer or lid over the mug. Covering matters more than people think. Horsetail is a tougher, more fibrous plant than something delicate like chamomile, so it needs a longer steep, and covering keeps the temperature up so the water can actually work on it.

Step three: steep 8 to 10 minutes

This is longer than you'd steep a black tea, and that's on purpose. Horsetail's silica and minerals sit inside a fairly stubborn plant structure. Five minutes gives you weak, watery tea. Eight to ten minutes gets you a fuller cup with that faint mineral note Peruvians recognize. If you're using loose herb and you want to go further, some Andean home cooks simmer it gently for a few minutes instead of just steeping, which extracts even more. Strain well afterward, since the fine plant bits can be gritty.

How much, how often

One cup a day is a reasonable place to start. Some people drink two, usually one in the morning and one in the early afternoon. Because horsetail nudges you toward the bathroom, most folks skip the evening cup so it doesn't interrupt sleep. We wouldn't push past two or three cups a day, and we wouldn't drink it every single day for months on end without a break. Horsetail contains an enzyme called thiaminase that can break down vitamin B1 (thiamine) over long, heavy use, which is a real reason not to treat it like your everyday water.

Making it taste good

Plain horsetail is grassy and a little dry on the tongue. A squeeze of lemon brightens it up nicely. A small spoon of honey rounds it out. In parts of Peru people blend cola de caballo with other kidney-friendly herbs rather than drinking it solo, which is exactly what the classic blends do, so if the flavor isn't for you, a mix might land better. It also cools well over ice on a hot afternoon, no sugar required.

Who should be careful

This part isn't optional reading. Because horsetail acts as a diuretic, it isn't a good match for anyone already taking a prescription diuretic (a "water pill"), and it can affect potassium levels. If you have kidney disease, heart trouble, or you're on any medication, talk to your doctor before making it a habit, not after. People who are pregnant or breastfeeding should skip it, since there's no safety data to lean on. And if you have a known allergy to it, or you drink alcohol heavily (which already burns through thiamine), horsetail is not for you. We're a tea shop, not a doctor, and this is the kind of herb where that distinction actually matters.

Brewed the way above, though, cola de caballo is a pleasant, low-drama daily tea with a long history in Peruvian homes. Start with one well-steeped cup, see how you like it, and go from there.

If you want to build a small kidney-and-urinary tea rotation, horsetail pairs naturally with dandelion root (diente de león) and the traditional Riñosan kidney blend, which already folds horsetail in with chanca piedra. You can browse the whole lineup in our kidney and urinary health collection.