UNDO_TBS table is growing constantly in Red Hat Network Satellite, do I need to worry about that?

Issue

While checking oracle db on RHN Satellite health one can notice that UNDO_TBS is constantly growing:

Tablespace                  Size    Used   Avail   Use%
DATA_TBS                    6.3G      5G    1.3G    79%
SYSAUX                      500M  236.5M  263.4M    47%
SYSTEM                      400M  255.3M  144.6M    64%
TEMP_TBS                   1000M      0B   1000M     0%
UNDO_TBS                    1.4G    1.2G    187M    88%
USERS                       128M     64K  127.9M     0%

As it was 100% used have added some extra space to it however, most of the 500MB added has been consumed up already (less then a day after adding extra space). And UNDO_TBS is still constantly growing. Why do one see this behaviour?