The fields of radiation effects in simple polymers and in biopolymers have been largely approached from very different aspects, although there are close analogies in many of these effects. Examples of these similarities in a number of cases include the influence of temperature, of oxygen, of certain additives, e.g., as radiation protectors, and of water with the indirect effect. Lessons learnt from the irradiation of polymers do not always appear to have been applied to more complex biological systems, and in particular the physical changes such as molecular configuration during irradiation, which can be of great importance on its subsequent behavior. The approximately similar G values for radical production as between these two systems, and the considerable difference in doses required may be taken to imply that it is molecular weight and arrangement rather than the behavior of a specific chemical constituent which is a key element in explaining this difference, which is also found in polymers of similar chemical structure but of different molecular weight. One may also consider whether molecular crosslinking as well as main chain scission is the vital factor in determining subsequent vitality of a macromolecular biological system. Linking two macromolecules together at only one point anywhere would greatly limit their subsequent behavior, e.g., separation and duplication, and would not face the same problem as in naturally occurring radiation-induced reaction.