We always go for a minimum of five, depending on the study. If you have 8 key informants you can use your data quantitatively. It's always nice to have more participants, but you can go with the data you have.

We always go for a minimum of five, depending on the study. If you have 8 key informants you can use your data quantitatively. It's always nice to have more participants, but you can go with the data you have.

Thank you so much for the advice sir. I really appreciate it.

I will be looking forward to read the paper one day.

I recomemnd you to check the Russell´s Bernard books named:

Handbook of Methods in Cultural Anthropology.

Research Methods in Anthropology: Qualitative and Quantitative Approaches.

you can calculate your data with 8 informants

You may take help from my papers for calculating ICF.

number of informants you can determine based on species are curve/ time curve

In the Journal of Ethnobiology and Ethnopharmacology are some papers related with ICF or FIC with important data.  

The quantitative formulas, I think, don't have determinate how many informants you must have. Ok. A minimum of five is good. But, if you have eight or more, ok too. But, if you have a lot of these, it's so beautiful, because your data are more interesting and give the best information.

You can use species  area curve/time curve to collect medicinal plant data from the informants.

Thanks to all respondents, bcoz I was seeking for same answer. I have 12 key informants data.

number of informant depends on the number of new information.

I would say 100 informants would be nice for study. More informants give you more confidence on your result. However, its always difficult to have large number of informants. You can get detail protocol from my articles given below. Thanks.

Article An ethnobotanical study of medicinal plants used by tribal a...

Article Ethnomedicinal survey of various communities residing in Gar...