Ashta Churnam is a herbal formulation in churna or powder form.
Its usage:

1. Loss of appetite, Indigestion, distaste,
   
2. Flatulence and Pain abdomen.

Dosage:
 ¼ to ½ teaspoon, two or three times daily administered along with ghee in first morsel of food or as directed by physician.
Side effects: May induce gastric irritation in higher dose, Used with caution in hypertensive patients as it contain salt.
Roga karma: Agnimandya, vatagulma, ajeerna and shula.
Dosha karma: Vatakaphahara.
Agni karma: Deepana
Other karma: Vatanulomaka, grahi, shulahara and srotoavarodahara
Ashta Churnam Ingredients:
Pippali  Piper longum    1 Part
Maricha                Piper nigrum     1 Part
Shunti   Zingiber officinalis          1 Part
Ajamoda              Carum roxburghianum  1 Part
Sainhava              Rock salt              1 Part
Sweta jeeraka   Cuminum cyminum        1 Part
Krishna jeeraka                Carom bulbocastanum  1 Part
Shuddha Hingu (Processed with Ghee)
Ferula asafoetida            1 Part
Preparation: The above ingredients are powdered separately and mixed together in specified quantity.
Reference : Sahasrayogam