Herein there was conducted a complex experimental investigation of the immediate effect of cleaning compositions, based on water, ethanol, and perchloroethylene, on the fibers and dyes of museum textiles. A microscopic technique was employed to measure a single and repeated deformation of the shape of microfibers of silk and wool, their diameter, and also a change of double refraction in silk. The number of breaks of peptide bonds in silk was evaluated by means of an acid histochemical dye. A spectrophotometric technique was used to study the extraction of red natural dyes of carmine acid and orcein from silk. Water and compositions, based on it, as well as the mixture ethanol: H₂O cause deformation of microfibers of silk and wool, irreversible changes in the regular microstructure, and breaks of peptide bonds in silk fibroin, as well as the extraction of red natural dyes of carmine acid and orcein from silk. A negative effect of these compositions increases as the age of the textile grows, after repeated wetting and drying, as well as for textiles containing different types of fibers. Tetrachloroethylene and compositions, based on it, have a far less effect on the fibers and dyes of museum textiles than compositions, based on water. -- AATA