The spreading of a sessile drop can be explained by a dynamic energy balance in which released excess capillary energy causes triple-line motion while wetting front speed is moderated by viscous dissipation within the liquid. This energy balance leads to a well-known relationship between dynamic and equilibrium contact angles and spreading speed. Experiments conducted with a silicone oil, poly( dimethylsiloxane), confirmed the validity of this equation. Similar experiments of spreading of tricresyl phosphate (TCP) on the same three substrates, glass, Halar (polyethylene-chlorotrifluoroethylene), and polypropylene, led to anomalous behavior : among other observations, we noted that the (apparent) spreading force needed for a given spreading speed was too high. Here, we suggest a tentative theory involving molecular orientation or conformation of the asymmetrical liquid molecules after they have been "laid down" on the solid substrates during spreading. As TCP molecules orientate near the triple line, the liquid/solid interfacial tension and therefore the local value of equilibrium contact angle are modified. The theory adequately explains several experimental results but leaves some unanswered questions.