文档介绍：怎样才能煎好中药
of rural drinking water sources, protection of drinking water sources in rural areas by the end of the致，一煎煎出率大约为30%，二煎为40%～50%，两次合并可得70%～80%。而三煎、四煎仅占20%。从中药煎煮机煎煮中药的角度来讲，煎煮次数过多，一不利于节约能源，二煎煮时成分可能发生变化。因而中药煎煮机一般采用一次煎煮。
  煎煮火候和时间  根据各类药剂的不同特点应用不同的火候和时间，可最大限度地煎出有效成分和保留有效成分。解表药应用武火速煎，头煎煮沸后煎10～15min，二煎煮沸后10min。一般药应先用武火煮沸，再用文武火交叉煎煮。头煎煮沸后20～25min，二煎煮沸后15～20min。滋补调理药先用武火煮沸，再用文火慢煎，使药汁浓厚，药力持久。头煎煮沸后30～35min，二煎煮沸后20～25min，如需三煎，煮沸后15min［1］。从药汤开算起，一般
of rural drinking water sources, protection of drinking water sources in rural areas by the end of the delimitation of the scope of protection, complete with warning signs, isolating network protection facilities
of rural drinking water sources, protection of drinking water sources in rural areas by the end of the delimitation of the scope of protection, complete with warning signs, isolating network protection facilities
of rural drinking water sources, protection of drinking water sources in rural areas by the end of the delimitation of the scope of protection, complete with warning signs, isolating network protection facilities
100g左右的药，有15～20min则可，如药量大可适当增加3、5分钟，如小可缩短一点，比如儿科用药有时就是20g左右，这时煎到水开后2、3分钟则可。煎药时间太长，药的味道难以下咽，而且变成了过沸水，水分子集团增大，影响水分子对细胞壁的渗透性。如果是花或叶为主的药，煎药时间应再缩短。
2  注意事项
  浸泡  煎药前中药饮片一定要浸泡，因为中药大多数是植物类干品，有一定的体积和厚度。因此，在煎煮前必须浸泡，使中药饮片湿润变软，细胞膨胀，产生一定的渗透压，使有效成分渗透扩散到细胞组织外部的水中，有利于有效成分的溶出。冬天若用20℃～30℃的温水浸泡可缩短煎煮时间，但