Study to Evaluate Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of AMG 181.

Inclusion Criteria:

- Body Mass Index (BMI) between 18 and 34 kg/m2

- Normal physical and neurological examination, clinical laboratory values and ECG

- Ulcerative Colitis Disease Activity Index (UCDAI, aka Mayo score) score of 4 to 10
(inclusive), with a minimum sigmoidoscopy score of 1; (for subjects with ulcerative
colitis)

- Crohn's Disease Activity Index (CDAI) score of >150 and < 450 at screening (for
subjects with Crohn's disease)

- Additional inclusion criteria apply

Exclusion Criteria:

- History or evidence of a clinically significant disorder (including psychiatric),
condition or disease that would pose a risk to subject safety or interfere with the
study evaluations, procedures or completion

- History of malignancy of any type, other than in situ cervical cancer or surgically
excised non-melanomatous skin cancers within the past 5 years

- Underlying condition(s) that predisposes the subject to infections

- Disease limited to the rectum, i.e. within 10 cm of the anal verge (for subjects with
ulcerative colitis)

- Evidence of severe disease (as evidenced by an Hb concentration less or equal to
10g/dL; toxic megacolon, or an UCDAI score greater than 10) (for subjects with
ulcerative colitis)

- Subject has short bowel syndrome (for subjects with Crohn's disease)

- Presence of an ostomy (for subjects with Crohn's disease)

- Presence of a fistula (for subjects with Crohn's disease)

- Additional exclusion criteria apply