Taste alteration (dysgeusia), an underrecognized toxicity associated with taxane-based chemotherapy (TaxCh), lacks standard treatment. We investigated prevention of dysgeusia with oral glutamine in patients undergoing first-time TaxCh. Adult patients were randomized to receive either 30 g/day glutamine or placebo (maltodextrin) from day 1 of TaxCh. Dysgeusia was measured daily with a visual analogue scale (VAS). On each chemotherapy cycle, objective (sour, sweet, salty, bitter) and subjective (four-category scale) taste and toxicity (National Cancer Institute Common Toxicity Criteria, v.3) were assessed. Stomatitis and zinc deficiency were treated. For primary outcomes, repeated dysgeusia scores were analyzed with a linear mixed model. Repeated data on each objective or subjective taste item were analyzed with a generalized estimating equation. Of 52 patients randomized, 41 completed treatment (median study duration, 74 days). At baseline, the glutamine (n = 21) and placebo (n = 20) groups were comparable for age (64 years), gender (32% men), tumor types, chemotherapy (docetaxel, 44%; paclitaxel, 56%), schedule (weekly, 78%; 3-weekly, 22%), treatment intention (15% adjuvant), dysgeusia (VAS, 11/100), and taste recognition (88%). Twenty-four patients had peripheral neuropathy grades 1-2; none had grade 3. Glutamine and placebo were not different for maximal dysgeusia and increase from baseline, with an insignificant linear time effect. Separate subgroup analyses for patients with baseline dysgeusia < or =11 or >11 did not alter the results. Objective or subjective taste tests were not different, neither were adverse events. Compared with placebo, oral glutamine did not prevent or decrease subjective taste disturbances or altered taste perception associated with TaxCh. The role of glutamine in supportive care of taxane-associated dysgeusia seems limited.