A nutritional assessment including determination of symptoms potentially influencing weight loss was prospectively performed on 254 consecutive cancer patients with favorable performance scores (Eastern Cooperative Oncology Group [ECOG] level 0 to 2). Primary cancer sites included the following: non-small cell lung (n = 93), colon (n = 50), prostate (n = 23), oropharyngeal (n = 18), breast (n = 15), gastrointestinal (n = 13), and other (n = 42). Thirty-nine percent of patients had received no prior chemotherapy or radiation therapy. Common symptoms in the population were abdominal fullness (61%), taste change (46%), constipation (41%), mouth dryness (40%), nausea (39%), and vomiting (27%). Current caloric intake was surprisingly similar in 170 patients with weight loss (percent usual body weight [PUBW], less than or equal to 95%) compared with 84 without weight loss (PUBW, greater than 95%; 31.4 +/- 1.5 versus 30.5 +/- 2.1 kcal/kg/d, respectively). Symptoms identified by multivariate analysis as occurring significantly more frequently in populations with weight loss included abdominal fullness (P less than 0.001), taste change (P less than 0.002), vomiting (P less than 0.005), and mouth dryness (P less than 0.02). There was no difference in frequency of symptoms between patients with or without prior chemotherapy. These results indicate that gastrointestinal/oral symptoms potentially influencing weight loss are prevalent early in the course of cancer patients with unresectable disease, regardless of current nutritional status, caloric intake, or prior therapy experience.