Iron pills

In the Videos

Bree takes her iron supplement pills to the park with her.

Bree is taking iron supplement pills as part of her preparation for the ceremony. This is first mentioned in the video In The Park. Daniel notices Bree taking pills, identifies them as iron pills, and asks if her dad is making her take them, which Bree refuses to answer.

Medical Uses

Iron pills are often prescribed for iron deficiency anemia. Iron deficiency is a problem because iron is the subtance in the blood that carries oxtgen, so if you don't have enough iron your cells won't get enough oxygen. Iron deficiency is caused by either not taking in (eating) enough iron, or by losing too much blood (excessive menstrual bleeding, for example).

Analysis

Some fans have speculated that Bree is taking the supplements to stave off anemia from excessive bleeding because her ritual involves drawing blood. This rumor has not been confirmed.

It could also be that her prescribed diet for the ceremony was low in iron, hence requiring that she supplement it with pills.