The invention relates to a probiotic functional food comprising: a biomass of Lactobacillus spp. strains conditioned to withstand temperatures of between -30 and -40 °C, and cryoprotective agents. Said food comprises jellies, desserts, juices and/or milk derivatives, preferably ice cream. This functional food is intended for patients undergoing therapies such as chemotherapy and/or radiotherapy, since it counteracts the side-effects cancer treatment.