In order to increase dietary folic acid intake and to improve nutritional status regarding folate by controlling homocysteine concentrations, ten patients with inflammatory bowel diseases (Crohn's disease in the colon and ulcerative colitis) received individualized nutritional guidance and were followed up as outpatients for 2 months. The following procedures were performed at the beginning of the study (T0), after 1 month (T1) and at the end of the study (T2): collection of anthropometric data (weight and height), dietary data (24 h diet recall), and blood under fasting condition for the determination of serum folic acid, homocysteine, C-reactive protein, and vitamin B12. Plasma folic acid deficiency was not detected but hyperhomocysteinemia was present in six individuals and C-reactive protein (CRP) was increased (>0.5 mg/dl) in seven patients. After the patients were instructed there was a significant increase in vitamin B6 intake (about 35%) and in folate intake (49.6%). Mean plasma levels of folic acid, homocysteine, and vitamin B12 did not change, but there was a significant decrease of CRP at T1, 0.36 mg dl(-1) on average (P = 0.01), which was maintained at T2. We conclude that the increased folate intake reported by this group of patients was not reflected in improved serum concentrations of folic acid and homocysteine. However, the guidelines for the patients probably induced them to choose a more adequate diet, providing nutrients that help control the inflammatory process.