LF is a mosquito-borne infection caused by the lymphatic dwelling parasites W. volvulus, of whom 270,000 are blind and 500,000 visually impaired. About 37 million persons are infected with O. While more than 90% of all onchocerciasis cases are found in 30 African countries, the rest occur in isolated foci that exist in Yemen and six countries in central and South America World Health Organization. The disease affects several millions of people in the world and is transmitted from host to host by the blood-feeding “blackfly” Simulium. Onchocerciasis or subcutaneous filariasis is a parasitic disease caused by O. The most common and persistent parasitic nematodes of humans are the soil-transmitted nematodes-roundworms ( Ascaris lumbricoides), whipworms ( Trichuris trichiura), hookworms ( Necator americanus and Ancylostoma duodenale) and thread worms ( Strongyloides stercoralis)-and the filarial nematodes that are responsible for lymphatic filariasis (LF) ( Brugia sp, Wuchereria bancrofti) and onchocerciasis ( Onchocerca volvulus). Parasitic nematodes constitute an enormous medical and veterinary burden in some parts of the world in the tropics, however, they represent a severe public health problem. Even though the total number of nematode species has been estimated to be over 1 million, only about 28,000 species have been described, with over 16,000 of these species being parasites of plants and animals (including humans). Nematodes are roundworms that belong to the phylum Nematoda or Nemathelminthes. In this review we will shed light on the discovery and application of natural plant derived products on human neglected diseases. Therefore, natural sources, such as plants, represent a major opportunity to discover new lead molecules. The current situation is aggravated by the fact that most people living in the endemic countries have a low-income profile, making the pharmaceutical market for the development of new medications financially unattractive to the private-research sector. Since vaccines and safe and affordable treatments are still lacking, there is an urgent need to discover novel therapeutics against these human health threats. These parasites are responsible for a high rate of mortality and morbidity each year in the respective endemic countries. Amongst others, these include the causative agents of trypanosomiasis, leishmaniasis, schistosomiasis, lymphatic filariasis and onchocerciasis. A variety of these diseases are caused by parasites that belong to the diseases of poverty or the so-called neglected tropical diseases. Infectious diseases have a significant impact in human heath stock. In this review article we will provide an overview of the current status of plant derived pharmaceuticals and their chemical modifications to target parasite-specific peculiarities in order to interfere with their proliferation in the human host. Some of the currently available drugs are chemically de novo synthesized, however, the majority of drugs are derived from natural sources such as plants which have subsequently been chemically modified to warrant higher potency against these human pathogens. Here, the selection of antiparasitic drugs varies between different organisms. Unlike most antibiotics, there is no “general” antiparasitic drug available. More than 1 billion people world-wide are directly exposed to tropical parasites such as the causative agents of trypanosomiasis, leishmaniasis, schistosomiasis, lymphatic filariasis and onchocerciasis, which represent a major health problem, particularly in impecunious areas. Infectious diseases caused by parasites are a major threat for the entire mankind, especially in the tropics.