AbstractWe present the development of surfactant‐free, silica‐free and fully biobased oil‐in‐water antimicrobial Pickering emulsions, based on the self‐assembly of β‐cyclodextrin and phytoantimicrobial oils (terpinen‐4‐ol or carvacrol). Undecylenic acid (UA), derived from castor oil, can be used as bio‐based drug to treat fungal infection, but is less effective than petroleum‐based drugs as azole derivatives. To maximize its antifungal potential, we have incorporated UA in fully biobased Pickering emulsions. These emulsions are effective against fungi, Gram‐positive and Gram‐negative bacteria. The carvacrol emulsion charged with UA is +390 % and +165 % more potent against methicillin‐resistant S. aureus (MRSA), compared to UA and azole‐based commercial formulations. Moreover, this emulsion is up to +480 % more efficient that UA ointment against C. albicans. Finally, remarkable eradication of E. coli and MRSA biofilms was obtained with this environmental‐friendly emulsion.