Immunomodulatory effects of Echinacea purpurae and Pelargonium sidoides in calves were investigated. Sixty 25-day-old nonvaccinated calves living in integrated farm unit were randomly selected and were divided into 5 treatment groups consisting of 12 calves each; 4 groups were receiving different amounts and/or times of Echinacea and Pelargonium and the control group received placebo. Blood levels of gamma-interferon, cytokine gene expression, lactoferrin and total IgG were analysed on days 0, 9, and 30. When levels for total IgG, gamma-interferon, mRNAs for the gamma-interferon, IL-1 beta, IL-4 and the tumour necrosis factor-alpha genes were compared from days 0 to 9 post-treatment, significant differences were found between treated and non-treated calves using various amounts of Echinacea and Pelargonium; a doses of 250 mg Echinacea and 62.5 mg Pelargonium for 5 days seems to be ideal. Echinacea purpurae and Pelargonium sidoides are able to modulate immune functions in calves.