With over 7,000 flavors available in the US, e-cigarettes have grown increasingly popular. However, little is known about their individual constituent chemicals nor their effects on lung epithelia. We purchased flavored e-liquids from the Vapor Girl (http://www.thevaporgirl.com/) to characterize both the chemical constituents and biological effects of different flavors on human bronchial epithelial cultures (HBECs) and CALU3 lung epithelia. We screened a range of e-liquid flavors and doses for effects on cell proliferation/viability as well as their ability to alter cell signaling (e.g. Ca2+ signaling). Ca2+ signaling regulates cell division, mucus secretion, ciliary beat frequency, and Cl-/fluid secretion in airway epithelia and is disrupted by cigarette smoke. Altered Ca2+ signaling could cause changes in cell homeostasis. Thus, we measured changes in cytosolic Ca2+ following acute e-liquid exposures as well as other components of Ca2+ signaling pathways (i.e. STIM1 puncta formation, kinase phosphorylation, IP3 generation). Cells were plated on glass coverslips or in multiwell plates and exposed to a range of e-liquid doses (v/v %) diluted into media either acutely (10 min) or over 24h. Cell proliferation/viability was measured using the MTT assay. Cytosolic Ca2+ changes were measures using Fura-2-AM. Relative kinase phosphorylation was measured using a Human Phospho-Kinase Array. IP3 generation was measured using a competitive ELISA. All assays were completed with HBECs and/or CALU3 cells except STIM1 puncta visualization, which used transiently transfected STIM1-mCherry HEK293 cells. We found that several flavors inhibited cell proliferation in a dose-dependent manner, including Banana Pudding (Southern Style) (BPSS). BPSS also elicited an acute cytosolic Ca2+ signal involving both the endoplasmic reticulum (ER) and store-operated Ca2+ entry (SOCE), formed STIM1 puncta, and altered phosphorylation of ERK1/2, which regulates STIM1 phosphorylation. Our data demonstrated that the BPSS-flavored e-liquid altered the ER/SOCE Ca2+-signaling mechanism in airway epithelia, which could have biological consequences to Ca2+-mediated innate defenses of HBECs exposed to BPSS e-cigarette aerosol long-term. This also suggested that other flavors may have the ability to alter cell signaling (e.g. Ca2+, etc.) and other important lung epithelial functions. Investigations into the effects of flavored e-cigarette aerosol on Ca2+-dependent aspects of innate defense are ongoing. We have also identified specific chemical constituents from BPSS using mass spectrometry and we aim to identify the individual constituents that alter cell Ca2+ signaling in flavored e-liquids.