The chalcedony amulet MFA 98.697, which originates from the famous Tyszkiewicz Collection, has been kept in Boston's Museum of Fine Arts since 1898. The object bears a Sumerian Kultmittelbeschwörung on a thorn bush (Sum. ĝeš kiši 16 , Akk. ašāgum), a shorter version of which was published by A.R. George in 2016. The present paper provides editions of both incantations, including some new readings. In addition to the philological analysis, it explores the magical-medical application of the thorn bush, which might have had an apotropaic use. The object presented here is of great importance, since it provides the first occurrence of an incantation on a particular plant written on a pendant that was used as an amulet during magical-medical activities in ancient Mesopotamia. [ABSTRACT FROM AUTHOR]