On December 22, 2000, at 0331 hours mountain standard time, a Bell 206-L3 helicopter, N288JB, sustained substantial damage when the pilot became ill and lost control 20 feet prior to touchdown at Cochise County Airport, Wilcox, Arizona. Critical Air Medical was operating the helicopter under the provisions of 14 CFR Part 91. The commercial pilot and two crewmembers sustained minor injuries. The positioning flight departed the Tuscon Medical Center about 0300, after delivering a patient, and was returning to its base at the North Cochise County Medical Center in Wilcox. Visual meteorological conditions prevailed and a company VFR flight plan had been filed. The pilot told the operator's chief pilot he tried to drink a glass of tea about 2 hours before the mission, but discarded it because it tasted bad. The pilot said he felt a little discomfort during the mission when he detected the tea taste again. After the mission he reported that he felt better, and did not expect any problems on the return to base. About 5 minutes from the base hospital, the pilot said nausea, sweating, and cramps suddenly overcame him, and he began to retch. He said it was a dark, moonless night, and rough terrain was below him. The airport was at his 12 o'clock position at 5 miles, so he elected to fly there rather than attempt an off-airport landing. He requested a sick sack about 1 minute prior to landing. About 20 feet above the touchdown point, the pilot doubled over due to severe cramping. This moved the cyclic forward and to the right. The main rotor blades contacted the ground, and the helicopter came to rest on its side.