Health care is a basic need to humans which can only be achieved with medicines with high efficacy against disease causing pathogens. Globally, gastrointestinal infections are major health concern particularly to travelers since over 60% visiting tropical and subtropical regions develop diarrhea. Herbal plants have been used for decades to treat gastrointestinal infections globally including Tharaka-Nithi County in Kenya. However, there is little information on the demography of herbalist and the plants used in treatment of gastrointestinal infections such as typhoid, cholera and shigellosis. A cross sectional survey was carried out involving thirty herbalists to assess their demographic data and to establish herbs commonly used to treat typhoid, cholera and shigellosis in Tharaka-Nithi County. Data collected was subjected to Chi square test of association and descriptive statistics and presented in percentages. There were more male herbalists (65.52%) in the study than female herbalist (34.48%). Most of the herbalist (65.52%) were aged above 70 years. There was a significant (p < 0.05) association between herbalists’ level of education and age (X2 (6, N = 30) = 17.349, p = 0.008). Most herbalists were found to have below primary education level 58.62%. Aloe vera, Aspilia pluriseta, Ficus sycomorus and Physalis peruviana were identified as commonly used plants for treatment of cholera with Aspilia pluriseta being most preferred (27%) by herbalist above the age of 70 years. Vangueria infausta, Eucalyptus globulus, Carissa edulis and Erythrina abysinnica were commonly used for treatment of shigellosis with Eucalyptus globulus being most preferred (58.6%) by herbalist above the age of 70 years. Erythrina abysinnica, Carissa edulis, Vangueria infausta and Eucalyptus globulus were commonly used for treatment of typhoid while 50.0% of herbalist above the age of 70 preferred Erythrina abysinnica. Most of the herbalists had below primary education level. In conclusion, herbal medicine is mostly dispensed by older people in Tharaka-Nithi County in Kenya. Different herbal plants are used in the treatment of cholera, shigellosis and typhoid.