The Apothecary Diaries 07 (Manga) by Natsu Hyuuga

After breaking a "curse" on the imperial heirs, a palace servant with training in herbal medicine is promoted up the ranks to food taster...and right into the thick of palace intrigue in this lushly illustrated historical mystery series! Maomao succeeds in saving Jinshi from a horrific fate, proving herself indispensable to the palace once more! But while she is given the chance to explain herself, Maomao has yet to learn that the treachery of the plot she has uncovered is woven deep into the fabric of the very palace in which she serves! To truly unpick the mystery, Maomao will need her patience and her copious wits about her... She'll also need to watch her back, as she comes face-to-face with the sinister La Kan...