When an experimentalist or a biological mechanism applies an external force onto a cell chemically sticking to its substrate, a reacting "suction" force, due to the slow penetration of the surrounding fluid between the cell and the substrate, opposes to the dissociation. This force can overcome other known adhesive forces when the process is sufficiently violent (typically 10^5^ pN). Its maximal contribution to the total adhesive energy of the cell can then be estimated to 2 10^-3^ J/m2. The physical origin of this effect is quite simple, and it may be compared with that leaning a "suction-cup" against a bathroom wall. We address the consequences of this effect on (i) the separation energy, (ii) the motion of the fluid surrounding the cell, more especially, on the pumping of the fluid by moving cells, and (iii) the inhibition of cell motion
