It IS possible to get ready-prepared pepper soup mix from African stores. However, I like to use freshly ground spices in addition to/or instead of the mix. There are a myriad of spices which vary from place to place and you may want to experiment to find which suits you best. Interestingly, most of them are used in traditional medicine, some applications of which have been proven under laboratory conditions.
These are some of the readily available ones, together with their commonly known native names, English (where available) and botanical names. Please note that this is by no means an exhaustive list. Most will also have other native names, and many may be used in other dishes. In addition, people from parts of the Delta area use tamarind and lemon grass in their pepper soups. I particularly like the latter in fish and seafood pepper soups.
Add fresh herbs such as parsley, mint, basil and scent leaf just before serving the soups for additional freshness, colour and flavour.