Addn. compds. of chloramphenicol palmitate (I) and Ca pantothenate (II) are prepd. by melting together stoichiometric amts. of I and II. Thus, 2246g. I and 476g. II are heated at 110.degree. under N with stirring 30 min. The obtained cold mass is then crushed and sieved to yield 4:1 adduct (III), 96%, m. 92-106.degree. (.alpha.) 35.degree. (MeOH), 25.degree. (EtOH 80%-H2O 20%). The antibiotic activity of III is that of the I contained. The ir spectrum of III is given and is different from the spectrum of an intimate mixt. of 4 moles of I and 1 mole of II. III is stable in nonpolar solvents (32 g./l. ether) and gives polymorphic crystals, m. 195-202.degree. (H2O). Other complexes (2:1 and 1:1) are obtained by the same method.