The invention relates to bacteria of the species Lactobacillus paracasei and/or compositions comprising Lactobacillus paracasei for use in preventing and/or treating a mental illness, a symptom affecting mental health and/or a condition associated with chronic stress, in a mammal. The invention further relates to methods and uses of said bacteria of the species Lactobacillus paracasei and/or compositions. The invention can be applied in restoring, maintaining, and/or promoting mental (including cognitive) health and has potential applications, inter alia, in the area of dietary and food supplements, medicaments and pharmaceuticals.
