The Apothecary Diaries, Volume 10 (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!

When two beautiful foreign envoys with designs on the Emperor come calling with a tale of old about a spellbinding courtesan who captured the imagination of their family patriarch, it’s up to Maomao to concoct a theatrical scheme to give the ladies a whopper of a story to take home! Later, Maomao goes back to sniffing around the Inner Court to find out the truth about the troubling prevalence of those foreign perfume oils that could spell disaster for the throne's future heirs...