  Stars with B[e] phenomenon comprise a very diverse group of objects in a
different evolutionary status. These objects show common spectral
characteristics, including presence of Balmer lines in emission, forbidden
lines, and strong infrared excess due to the dust. The observations of emission
lines indicate the illumination by ultraviolet ionizing source, which is a key
part to understand the elusive nature of these objects. We study the
ultraviolet variability of many B[e] stars to specify the geometry of the
circumstellar environment and its variability. We analyse massive hot B[e]
stars from our Galaxy and from Magellanic Clouds. We study the ultraviolet
broad-band variability derived from the flux-calibrated data. We determine
variations of individual lines and its correlation with the total flux
variability. We detected variability of the spectral energy distribution and of
the line profiles. The variability has several sources of origin, including the
light absorption by the disk, pulsations, LBV-type variations, and eclipses in
the case of binaries. The stellar radiation of most of B[e] stars is heavily
obscured by circumstellar material. This suggests that the circumstellar
material is not present only in the disk but also above its plane. The flux and
line variability is consistent with a two-component model of circumstellar
environment composed of the dense disk and ionized envelope. The observations
of B[e] supergiants show that many of these stars have nearly the same
luminosity of about $1.9\times10^{5}\,L_\odot$ and similar effective
temperature.
