Blastocystis hominis is an enteric parasite that inhabits the gastrointestinal tract of humans and many animals. This emerging parasite has a worldwide distribution. It is often identified as the most common eukaryotic organism reported in human fecal samples that showed a dramatic increase in recent years. Metronidazole is the main therapy for blastocystosis. However, frequent reports of treatment failure suggesting isolates resistance to metronidazole. This study determined the growth pattern and in vitro susceptibility of B. hominis to nitazoxanide (NTZ), garlic, ginger, onion and turmeric. Fecal samples positive for Blastocystis were collected from patients with irritable bowel syndrome (IBS), and processed for culture. Cultured samples were subjected to examination by light microscopy. Herbs' extracts was freshly prepared. Drug susceptibility assays was done using 0.1 mg/ml of NTZ, garlic, ginger, onion and turmeric. Effects assessed on parasite culture after 24 hr. and 48 hr. Cultured fecal samples of B. hominis have identified several forms of the organism; vacuolar, granular, amoeboid and cyst forms within 24 hr. Nitazoxanide treatment significantly (P <0.001) lowered the parasite number after 48 hr. (mean, 337.5±17.67) /ml. The reduction rate after 48 hr. compared to PBS was 93.33%. Ginger treatment significantly (P <0.002) lowered the number of the parasite after 48 hr. (mean, 335±7.07) /ml. Moreover, garlic treatment also significantly (P < 0.002) lowered the number of the parasite after 48 hr. (mean,382.5±10.60) /ml. The reduction rates after 48 hr. in these treated samples compared to PBS were 92.98% and 92.44% respectively. However, onion, and turmeric treatments insignificantly lowered the number of the parasite after 48 hr. (P <0.15 & <0.22 respectively).