Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
guttŭla, ae, f. dim. [gutta], a little drop (ante- and post-class.): ah, guttula pectus mihi ardens aspersisti, Plaut. Ep. 4, 1, 27: favorum guttulae, Paul. Nol. Carm. 21, 427.