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Katak / Clearing Nut (Strychnos Potatorum)- Ayurvedic Properties, Effects On Doshas & Dosage


Ayurveda is the oldest science in the world that helps the human body to regain its strength and to promote longevity with proper maintenance. This path has been developed many years ago by the rishi-munis in various treatises and manuscripts in which various modes and means are included such as various herbal medicines, proper diet, and a healthy lifestyle. Ayurveda says unique facts that should be maintained by proper phenomena for achieving holistic health. Ayurveda believes in maintaining the harmony of the body-mind-soul with the surroundings and nature which helps the body to achieve equilibrium in the body. There are many herbs that are used as medicines, for different types of diseases. Ayurveda is a science that doesn’t only work on symptoms but also helps to cure the disease from its roots. It builds strength in our body, lowers stress levels, fights various ailments that come like pandemics, and helps with rejuvenating properties. In this article, we are going to discuss such wonderful herb Katak and its various health-promoting properties.

Katak, Clearing nut, Strychnos potatorum

General Information

In the traditional system of medicine, Katak is a herb, its botanical name is Strychonas potatorum and in English, it is termed as Clearing Nut, which is widely used to treat eye disorders, anorexia, diarrhoea, renal calculi, and many more illnesses. This herb is widely famous by the name of Nirmali in Hindi, titan - kothayi in Tamil, Chillachetu in Telugu, in Punjabi it is named Nirmali. It is widely found in South India and Eastern India. This herb has incredible health benefits, they all made it one of the important herbs in the Ayurvedic system. It is used in the treatment of various diseases in Ayurveda due to its therapeutic properties of Kapha and vata dosha shamak.

Special Note About This Plant

  • This herb is a potent herb for diabetes because it has special properties that help to provide relief from various eye disorders.
  • In Charak Samhita, this is categorised under the Vishaghna mahakashaya.
  • In Sushruta Samhita, this herb is described under the Parushkadi Ganna.
  • In Bhavprakash Nighantu, Raj Nighantu and Shodhal Nighantu - Chandanadi varga.
  • In Kaiyyadev Nighantu, this herb is described with special health benefits and different therapeutic properties.
  • In Dhanvantari Nighantu, there is also a description of this herb with its proper indications.

Ancient Verses

Shloka - 1

कतं कतफलं कात्यं श्लक्ष्णं वारिप्रसादनम्।
तोयप्रसादनफलं चक्षुष्यम् लेखानात्मकं।।
कतकम् तू वरं तिक्तम् विशदं शीतलम् लघु ।
विकाशि मधुरं छेदि चक्षुष्यम् कफवातनुत्।।
तृष्णां दाहं विषं गुल्मं हन्ति तोयमलापहम्।
तस्यैव च फलं पक्वं वातकृन्मेहनाशनम्।।
सुपिच्छिलं छर्दिकरं श्लेष्मपित्तप्रसेककृत्।
कतकस्य च मूलं तू सर्वकुष्ठप्रणाशनम्।

Reference - Kaiyyadev Nighantu

Interpretation of Shloka - This herb is used as Vaariprasadanam (clearing the water), its fruit is used as the best healing medicine for the eyes and can be used for scrapping. This herb is tikta (bitter), vishad, coolant and is light in properties,  fast in action, sweet in taste, and is widely used to pacify Kapha and vata dosha. This herb is useful to rectify dehydration, burning, poisoning, ascites, along with its fruit helps to relieve the vataj meha roga, this is unctuous, enhances the emetic feeling, used for Kapha-pitta pacification, this relives swellings, anemia, sinusitis, jaundice, and any type of poisoning condition.

Shloka - 2

पयःप्रसादी कतक:कतकम् तत्फलं च तत्।
कतकस्य फलं नेत्र्यम् जलनिर्मलताकरम्।।
वातश्लेष्महरम् शीतं मधुरं तुवरम् गुरु।।

Reference - Bhavprakash Nighantu / Amradiphala Varga

Interpretation of Shloka - This herb is used also called Paya prasadi, katak and nirmali. Its fruit is named Katak and is neuter. It is sweet and astringent in taste, good for the eyes, helps to clean out the water, is heavy, and is good for pacifying the Vata and Kapha dosha.

Shloka - 3

कतकम् शीतलम् प्राहुस्तृष्णा विषविनाशनम्।
नेत्रोत्थरोगविध्वंसी विधिनाञ्जनयोगतः।।
कतकस्य फलं तिक्तम् चक्षुष्यम् शीतलम् मृदु।
वारिप्रसादनम् कृच्छ्रशर्करामश्मरीं जयेत्।।

Reference - Dhanwantri Nighantu / Chandanadi Varga

Interpretation of Shloka - Katak herb is a coolant, helps to heal thirst, cures poisoning, treats various eye ailments, and is used as Anjan in the eyes. Its fruit is cold, tikta (bitter), mridu (soft), chakshushya (good for eyes), cleanses water, dysuria, and renal calculus.

Systemic Classification

  • Botanical Name - Strychnos potatorum
  • Family - Loganiaceae
  • Genus - Strychnos
  • Species - S. potatorum


  • Payahprasadi - is mainly used to purify the water.
  • Chakshushya, Nirmali - this helps in clearing the eyes.
  • Tiktaphala - bitter in taste.


  • This is a medium-sized, glabrous tree with a height of 10-15 metres and a thickness of .5 to 1 metres.
  • Its bark is 1.32 cm thick, its colour is black, corky skin, with narrow ridges that are very deep and narrow, its bark breaks easily.
  • Nodular branches on the origin.
  • Leaves are sessile, ovate, acute, glabrous, shining and three or five nerves consisting of the lower part of the disease.
  • Its flowers are fragrant, white in colour, and covered by leaves.
  • Its fruits are like berries in shape when ripened, globose, 12 cm in diameter white in colour, with shiny skin and also the appearance of silky hair.
  • In September and October blooming occurs and the fruiting time is in December.
  • This medicinal plant has various medicinal properties that act with diaboline, loganine, sucrose and stearic acid.

Ayurvedic Properties

  • Rasa (Taste) - Madhur (Sweet), Tikta (Bitter), Kashaya (Astringent)
  • Guna (Quality) - Laghu (light)
  • Veerya (Potency) - Sheeta (Cold)
  • Vipaka (Post digestive effect) - Madhur (Sweet)
  • Karma (Action) - Balances the Vata and kapha dosha
  • Projyang (Part used) - Seeds are used

Effects On Doshas

This herb balances the Vata and kapha dosha, with the help of kashaya and tikta rasa this herb will help to pacify the Kapha dosha and with the help of Madhur rasa, this herb will pacify vata dosha.

This herb is used traditionally to clean out the water so put this herb into the ponds or it can also be added to the water-filled vessel to put the impurities down from the water.

Practical Uses

  • As its name indicates, this herb is helpful in clearing the water.
  • By Acharya Priyavat Sharma this herb is categorised under the chakshushaya Varga so it means it effectively works upon eye disorders.
  • Due to its kashaya and tikta rasa, it also helps in enhancing the digestive fire, to increase the interest in eating the food.
  • This is good for its scraping properties, and so that’s why it is also used by mixing with Anjan or kajal and it will give you a positive impact on chronic eye pain, reduces pterygium, and other Kapha vata pradhan diseases.
  • Its seeds powder mixed with honey can help us to heal abscesses.
  • This herb is very helpful as a diuretic and helps to break the stones.
  • This herbal medicine root mainly works with skin disorders.
  • Katak is also helpful in digestion-related disorders like acidity, gastritis, diarrhoea, and gulma.
  • This also works upon the retention of urine.
  • The paste of the roots of this herb is used to treat eczema and pruritus over the skin.
  • When the decoction of seeds is prepared with some amount of Curcuma longa herb(Haldi) then it can help in controlling and reducing the amount of blood sugar within the body.
  • The powder of seeds used with honey will help in controlling the liver functions and works upon jaundice, anaemia, and any related disease.
  • Its unripened fruit is used in various toxic conditions or poisoning cases.
  • Moderately ripened katak fruit will balance the Kapha pitta dosha but is somewhat heavy to digest.


  • The powder can be used in the quantity of 1 to 3 grams.
  • If this herb is used as the vamak dravya then it can be used in the quantity of 6 grams.
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Author Bio:

Best Ayurvedic Doctor - Dr. Meenakshi Chauhan

Dr. Meenakshi Chauhan


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Reviewed By:

Best Ayurvedic Doctor in Mohali - Dr. Vikram Chauhan

Dr. Vikram Chauhan


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