Srotas in Ayurveda: The Body's Channels and How the Texts Describe Them

Srotas is the Sanskrit word for a channel, stream or passage. In Ayurveda it names the many pathways through which the texts say substances and functions move in the body: breath, food, water, the tissues, waste and even thought. The tradition teaches that free flow in these channels is health, and that disease is linked to their being blocked, overflowing or leaking.

This page describes the main channels as the classical texts present them, the four ways the tradition says they can go wrong, and the way the idea relates to modern anatomy. The srotas are a framework of a traditional medical system. They are not the same as blood vessels, nerves or the gut, and this page does not give a method of diagnosis.

What the texts say

The Charaka Samhita devotes a chapter to the srotas, in the section on specific topics, and treats the body as a system of channels as well as of tissues. It says that the body contains channels of many sizes and that every substance that moves does so through a channel suited to it. The Sushruta Samhita also describes channels in its teaching on anatomy and counts them differently, and the two texts do not agree on every point. Where they differ, we say so.

The channels are not thought of as only physical tubes. The tradition treats them as pathways of function as well as of matter, so that a channel is both a structure and a process. It is one reason the srotas cannot be mapped neatly onto the modern body.

The main channels

The Charaka Samhita names thirteen srotas, which can be grouped as follows.

• Channels that carry what enters the body. Pranavaha srotas carries the breath and vital energy, udakavaha srotas carries water and fluids, and annavaha srotas carries food through the digestive tract.
• Channels of the seven tissues. There is a channel for each dhatu: rasavaha for plasma, raktavaha for blood, mamsavaha for muscle, medovaha for fat, asthivaha for bone, majjavaha for marrow and nerve tissue and shukravaha for reproductive tissue.
• Channels of waste. Mutravaha carries urine, purishavaha carries stool and swedavaha carries sweat, the three malas.

Teachers sometimes add a channel of the mind, and the Sushruta Samhita and later writers give other counts, including extra channels for women connected to menstruation and lactation. The number is therefore not fixed across the tradition.

The root and the course of each channel

For each channel, the texts name a root, a place from which it arises. For example, the root of the pranavaha channel is described as the heart and the channels connected with it, and the root of the annavaha channel as the stomach and the left side of the body. These roots are assigned by the texts using the logic of their own anatomy, and they should be read as tradition and not as a modern description. The roots help practitioners to think about which part of the body to attend to for a given pattern of complaint.

Four ways channels are said to go wrong

The Charaka Samhita describes four ways a channel can be disturbed.

1. Excess flow, in which a channel carries too much, such as too much sweat or urine.
2. Obstruction, in which flow is blocked.
3. Nodular growth in the channel, a swelling or lump, in the old term.
4. Flow in the wrong direction, in which something moves by a route that is not its own.

These four are a teaching framework, and each is used by practitioners to describe patterns they observe. They are not medical diagnoses, and the same observation can have many modern explanations.

The link to other ideas matters here. The tradition says that ama, the residue of poor digestion, is one thing that can obstruct a channel, and that a vitiated dosha can travel through a channel and settle where the channel is weak. This is the picture on which classical advice about diet and routine rests.

Habits the tradition connects with healthy channels

These are general wellbeing habits, not treatments.

• Regular movement. Teachers say that exercise, walking and yoga keep the channels open. Modern guidance on activity for circulation is consistent with this, although it does not use the idea of srotas.
• Warmth and moisture in measure. Not too much cold or dryness, as the guides to vata and kapha discuss.
• Regular eating and drinking. Food and water of the right kind and amount, not too much or too little.
• Answering the natural urges. The pages on the malas discuss this.
• Breathing practice. The tradition connects pranayama with the breath channel, and the practices section covers it with safety notes.

What modern research says

The srotas are not recognised in modern anatomy. Researchers have noticed that some channels correspond loosely to known systems, such as the digestive tract, the airways, the urinary tract and the blood vessels, but others, such as the channels of the mind, have no equivalent, and no study has validated the srotas as a diagnostic framework. Statements that a treatment clears a channel should be treated with caution, and no such claim is made here.

Safety notes

Reading about the srotas is harmless. Practices said to open or cleanse the channels, such as fasting, purgative or emetic treatments, nasal practices, enemas and strong herbs, are not harmless for everyone and should be done only after medical advice and under a qualified practitioner. They are not suitable without a doctor’s agreement in pregnancy, breastfeeding, childhood, old age, diabetes, heart, kidney or liver disease, or with regular medicines.

Chest pain, breathlessness, swelling of a limb, sudden weakness, severe pain, blood in stool or urine and any other sudden or severe change are matters for urgent medical care. In India call 112 in an emergency.

This page describes a traditional framework. The medical disclaimer explains its limits. Any health concern belongs with a doctor, and Ayurvedic treatment with a registered practitioner (BAMS in India).

Frequently asked questions