Background Safe and adequate blood supply is the ultimate goal of blood transfusion services. Apparently, donor retention is more cost‐effective than donor recruitment. Furthermore, repeated blood donors showed lower prevalence of transfusion transmitted infection than first time donors. At present, approximately 70% of blood donors at National Blood Centre, the Thai Red Cross Society were repeated blood donors. Therefore, donor retention is considered the key success of blood safety and adequacy.Aims To focus on “donor care, the change we need” by decreasing the number of two main adverse effects of blood donation, which were fainting and anaemia in blood donors.Materials and Methods (i) To prevent blood donors from fainting, donors were asked to drink approximately 400 ml (four glasses of 100 ml) of water within 20 min prior to blood donation. The donors were closely observed during and after blood donation for any adverse effects. Information and education regarding the useful effect of water on blood donation were provided to the donors by poster, brief presentation and VDO presentation. The findings were recorded and analysed. (ii) To prevent blood donors from anaemia, the study group of 435 subjects was deferred from blood donation because of anaemia [haemoglobin (Hb) <12 g/dl for females and <13 g/dl for males]. Among these, there were 370 females and 65 males and 80% were repeated donors. Hundred tablets of ferrous fumarate (66 mg elemental iron), three tablets per day, were prescribed for each subject. Haemoglobin was determined using Automatic hematology analyzer (Cell Dyn 1700, Abbott Diagnostic, Santa Clara, CA, USA) and serum ferritin (SF) was determined using Immunoassay (AxSYM Ferritin Reagent Pack, Abbott Diagnostic). Counselling on nutrition and iron supplementation was provided to each individual. (iii) Both were in the period of months.Results (i) It was observed that the percentage of fainting after donation was decreased from 10·87 to 3·14% within 3 months at the study site. (ii) Baseline; 80 (18·39%) of 370 of females and 7 (1·61%) of 65 males were first time donors, whereas the rest were repeated donors. One hundred and seventy‐one cases (40·52%) were iron deficiency anaemia (female, Hb <12 g/dl, male Hb <13 g/dl, SF ≤15 ng/ml), whereas 29 cases (6·87%) were non‐anaemic iron deficiency (normal Hb, SF ≤15 ng/ml).After Iron Supplementation Haemoglobin and SF in females and males were significantly increased. Among these, 41·15% were able to return for blood donation after 1 month onward.Conclusion and Recommendation (i) Sufficient water intake before blood donation will significantly decrease fainting because of vasovagal adverse reaction in blood donation. (ii) There is an increase risk of iron deficiency anaemia because of blood donation, which is more evident in females. Iron supplement of 50 tablets (66 mg elemental iron) is usually sufficient per one unit of whole blood donation. However, SF should be monitored at least once a year in order to maintain SF level up to 50–100 ng/ml.