Kithul flour, also known as Kithul piti, is a traditional, gluten-free flour made from the pith of the Kithul palm tree (Caryota urens), native to Sri Lanka and other parts of South Asia. It is a highly valued and nutritious ingredient, particularly in Sri Lankan cuisine.

The process of making Kithul flour is labor-intensive. After a Kithul palm is felled, the starchy pith from the trunk is extracted, dried, and then ground into a fine powder. The resulting flour has a creamy white color and a very subtle, mild flavor.

Kithul flour is most famously used to make Kithul Thalapa (a traditional steamed pudding) and Halapa (a sweet wrapped in a Kithul leaf). It is also used as a thickener in curries and gravies and to make various other local sweets and confections.

Nutritionally, it is known for being a good source of carbohydrates and is believed to have a low glycemic index, making it a healthier alternative to refined flours. It is also thought to have properties that are beneficial for cooling the body and aiding digestion, according to traditional beliefs.