The feeding behavior of gall-inducing organisms is one of the determinant factors for the neoformations induced in host plant tissues. By using literature data to review phloem traits in galls, we document the state of the art and point out gaps in the knowledge. In general, there are few records of phloem aspects in galls, but the phloem related changes have been reported predominantly for insect and nematode galls. Among the insects, the Aphididae (Hemiptera), which feed on the phloem sap, represents one of the largest groups of gall inducers whose galls are models of study on phloem alterations. The studies that bring results from phloem comprise predominantly anatomical analysis, while data on immunocytochemistry, genetics, and cytology are incipient, and regarding Hemiptera galls are unknown to science. Under the influence of the gall inducers, the phloem cell hypertrophy, proliferation, and atypical development imply in the increasing availability of feeding sites and supplying gall tissues with nutrients. The gaps in the description of phloem characteristics under the influence of the diverse groups of gall inducers may be due to technical difficulties in assessing phloem cells.